Prevent a trait from being applied to a given object

For various reasons, a rule may want to prevent the future "don" of a given trait for a given object.

I propose the use of the "ward" macro, as follows:

Thing t = ward( $core, BannedTrait.class );

If another rule, at a later point, will try to apply the BannedTrait or any of its subtypes to $core, that trait will not be applied to $core and (potentially) an exception will be thrown.

Details:
$core can be a @Traitable object or a Thing (i.e. an instance of a trait proxy). THe "ward" operation automatically applies the "Thing" trait to $core in case it has not been done yet.

Optionally, one might use the "grant" macro to undo a ward (suggestions for a better name are encouraged).

This feature will help in the implementation of "disjunct" or "mutually exclusive" traits, which are incompatible and can't be applied to the same