1. what is the "default value"
I think the meaning of "default value" should describe the behavior when the value is not explicit set by user in the SriovOperatorConfig object. In my Test 4 and 5, both functions are disabled in the operator when the object creation does not include the attributes in question.
The value of '<none>' , i.e. not returned, should match with the "default value". In your my 3 even when the user has set false for both, '<none>' is still returned, which to me indicates default value is false for both.  

2. attribute value returned in get should be consistent.
The get behaviour should not change resulting documentation regardless of how the attributes are set.
In my Test 3, when both attributes are set to false in initial object creation, get does not return any value for those attributes.
However, if object attribute was patched to false, the get returns them.

    4.18.z

    Easily on both SNO and multi-node cluster. 

   I checked in different ways, please check all the tests and scenarios and my observations. 


Test 3: Setting the values FALSE at the time of creating CR.


1]
~~~
[root@vm-236-142 ~]# cat << EOF| oc create -f -
apiVersion: v1
kind: Namespace
metadata:
  name: openshift-sriov-network-operator
  annotations:
    workload.openshift.io/allowed: management
EOF
namespace/openshift-sriov-network-operator created


2]
~~~
[root@vm-236-142 ~]# cat << EOF| oc create -f -
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
  name: sriov-network-operators
  namespace: openshift-sriov-network-operator
spec:
  targetNamespaces:
  - openshift-sriov-network-operator
EOF
operatorgroup.operators.coreos.com/sriov-network-operators created


3]
~~~
[root@vm-236-142 ~]# cat << EOF| oc create -f -
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: sriov-network-operator-subscription
  namespace: openshift-sriov-network-operator
spec:
  channel: stable
  name: sriov-network-operator
  source: redhat-operators
  sourceNamespace: openshift-marketplace
EOF
subscription.operators.coreos.com/sriov-network-operator-subscription created


4] CR does not get created automatically, we need to create manually as mentioned in the documentation.
~~~
[root@vm-236-142 ~]# oc get SriovOperatorConfig
No resources found in test namespace.


5] While creating the CR, I set the values in the spec field to be false. 
~~~
[root@vm-236-142 ~]# cat <<EOF | oc create -f -
apiVersion: sriovnetwork.openshift.io/v1
kind: SriovOperatorConfig
metadata:
  name: default
  namespace: openshift-sriov-network-operator
spec:
  enableInjector: false           <<<
  enableOperatorWebhook: false           <<<
  logLevel: 2
  disableDrain: false
EOF
sriovoperatorconfig.sriovnetwork.openshift.io/default created


VERIFICATION:
~~~

1] There are no injector and webhook pods are running in the namespace. 
~~~
[root@vm-236-142 ~]# oc get pods
NAME                                      READY   STATUS    RESTARTS   AGE
sriov-network-config-daemon-2lv5l         1/1     Running   0          62s
sriov-network-operator-548c568f46-v4zd5   1/1     Running   0          10m


2] Setting the values false at the time of CR creation, gives the <none> output. However as per the behaviour 'none' is equivalent to false as per the testing. 
~~~
[root@vm-236-142 ~]# oc -n openshift-sriov-network-operator get SriovOperatorConfig -o custom-columns='Name:.metadata.name,Injector:.spec.enableInjector,OperatorWebhook:spec.enableOperatorWebhook'
Name      Injector   OperatorWebhook
default   <none>     <none>           <<<


3] Deleted the CR and recreated it again by setting the values true.
~~~
[root@vm-236-142 ~]# oc delete SriovOperatorConfig default
sriovoperatorconfig.sriovnetwork.openshift.io "default" deleted

[root@vm-236-142 ~]# oc get SriovOperatorConfig
No resources found in openshift-sriov-network-operator namespace.


4] Recreated CR with true. 
~~~
[root@vm-236-142 ~]# cat <<EOF | oc create -f -
apiVersion: sriovnetwork.openshift.io/v1
kind: SriovOperatorConfig
metadata:
  name: default
  namespace: openshift-sriov-network-operator
spec:
  enableInjector: true           <<<
  enableOperatorWebhook: true           <<<
  logLevel: 2
  disableDrain: false
EOF
sriovoperatorconfig.sriovnetwork.openshift.io/default created


5] Here I observed, if we create the CR with default values which are supposed to be true then it shows 'true'. Later on we can perform the patch to make it false, post patching it updates the value and set to false. 
~~~
[root@vm-236-142 ~]# oc get pods
NAME                                      READY   STATUS    RESTARTS   AGE
network-resources-injector-shqnk          1/1     Running   0          9s
operator-webhook-lrzwf                    1/1     Running   0          9s
sriov-network-config-daemon-pwnvk         1/1     Running   0          9s
sriov-network-operator-548c568f46-v4zd5   1/1     Running   0          17m

[root@vm-236-142 ~]# oc -n openshift-sriov-network-operator get SriovOperatorConfig -o custom-columns='Name:.metadata.name,Injector:.spec.enableInjector,OperatorWebhook:spec.enableOperatorWebhook'
Name      Injector   OperatorWebhook
default   true       true           <<<

[root@vm-236-142 ~]# oc patch sriovoperatorconfig default --type=merge -n openshift-sriov-network-operator --patch '{ "spec": { "enableInjector": false } }'
sriovoperatorconfig.sriovnetwork.openshift.io/default patched

[root@vm-236-142 ~]# oc patch sriovoperatorconfig default   --type=merge -n openshift-sriov-network-operator   --patch '{ "spec": { "enableOperatorWebhook": false } }'
sriovoperatorconfig.sriovnetwork.openshift.io/default patched

[root@vm-236-142 ~]# oc -n openshift-sriov-network-operator get SriovOperatorConfig -o custom-columns='Name:.metadata.name,Injector:.spec.enableInjector,OperatorWebhook:spec.enableOperatorWebhook'
Name      Injector   OperatorWebhook
default   false      false           <<<


Test 4: <none> SCENARIO on SNO cluster:
~~~

1] Created CR without the parameters "enableInjector and enableOperatorWebhook". 
~~~
[root@vm-236-142 ~]#  cat <<EOF | oc create -f -
apiVersion: sriovnetwork.openshift.io/v1
kind: SriovOperatorConfig
metadata:
  name: default
  namespace: openshift-sriov-network-operator
spec:
  logLevel: 2
  disableDrain: true
EOF
sriovoperatorconfig.sriovnetwork.openshift.io/default created


2] VERIFICATION: Default value seems to be set to false. The Documentation says "By default, this field is set to true." However in practical the default value is false which gives <none> output; unless we specify expilicitly to be true. 
~~~
[root@vm-236-142 ~]# oc get pods
NAME                                      READY   STATUS    RESTARTS   AGE
sriov-network-config-daemon-x5jf2         1/1     Running   0          9s
sriov-network-operator-548c568f46-v4zd5   1/1     Running   0          60m

[root@vm-236-142 ~]#  oc -n openshift-sriov-network-operator get SriovOperatorConfig -o custom-columns='Name:.metadata.name,Injector:.spec.enableInjector,OperatorWebhook:spec.enableOperatorWebhook'
Name      Injector   OperatorWebhook
default   <none>     <none>           <<<



Test 5: <none> SCENARIO on multi-node cluster:
~~~

MULTI-NODE CLUSTER:
~~~
[ocp418@vm-236-142 ~]$   cat <<EOF | oc create -f -
apiVersion: sriovnetwork.openshift.io/v1
kind: SriovOperatorConfig
metadata:
  name: default
  namespace: openshift-sriov-network-operator
spec:
  logLevel: 2
  disableDrain: true
EOF
sriovoperatorconfig.sriovnetwork.openshift.io/default created

[ocp418@vm-236-142 ~]$ oc get pods
NAME                                      READY   STATUS            RESTARTS   AGE
sriov-network-config-daemon-642g9         0/1     PodInitializing   0          4s
sriov-network-config-daemon-979cr         0/1     PodInitializing   0          4s
sriov-network-config-daemon-p8b5v         0/1     PodInitializing   0          4s
sriov-network-operator-548c568f46-vmvnq   1/1     Running           0          2d3h

[ocp418@vm-236-142 ~]$ oc get pods
NAME                                      READY   STATUS    RESTARTS   AGE
sriov-network-config-daemon-642g9         1/1     Running   0          8s
sriov-network-config-daemon-979cr         1/1     Running   0          8s
sriov-network-config-daemon-p8b5v         1/1     Running   0          8s
sriov-network-operator-548c568f46-vmvnq   1/1     Running   0          2d3h

[ocp418@vm-236-142 ~]$   oc -n openshift-sriov-network-operator get SriovOperatorConfig -o custom-columns='Name:.metadata.name,Injector:.spec.enableInjector,OperatorWebhook:spec.enableOperatorWebhook'
Name      Injector   OperatorWebhook
default   <none>     <none>    <<<
~~~     

    [ocp418@vm-236-142 ~]$ oc -n openshift-sriov-network-operator get SriovOperatorConfig -o custom-columns='Name:.metadata.name,Injector:.spec.enableInjector,OperatorWebhook:spec.enableOperatorWebhook' Name Injector OperatorWebhook default <none> <none> <<<

    [root@vm-236-142 ~]# oc -n openshift-sriov-network-operator get SriovOperatorConfig -o custom-columns='Name:.metadata.name,Injector:.spec.enableInjector,OperatorWebhook:spec.enableOperatorWebhook' Name Injector OperatorWebhook default false false <<<

    REFERENCE: https://docs.redhat.com/en/documentation/openshift_container_platform/4.18/html/networking/networking-operators#sr-iov-operator