Current implementation shows errors and warning under item selected for installation.
See confirmation page error message for virtualbox Installer here.

Confirmation page controller should run Virtualization detection along with installed components detection and show warning under virtualbox item if it is detected or selected for install.

If Virtualization firmware status cannot be detected (windows 7) message should say:

• Make sure hardware virtualization is enabled on your platform if supported to improve performance.

if Hardware Virtualization is Disabled:

• Please enable hardware virtualization for your platform to improve performance

If Hardware Virtualization is Enabled, no message is required.