In mojoBaseBage we have methods to validate view permissions so you can protect a view page in a feature with:
we also have method to validate Edit Permisions like this:
These methods verify also that the page contains the module and determines view or edit permissions based on page and module permissions.
The only other scenario that I can think of in an existing feature is like in the forums where a user does not need edit permissions to post, so the forum postedit page chacks view permissions and checks module permissions whether anonymous posting is allowed.
So, it depends on your feature, we have helper methods for view and edit permissions,but it is also possible for you to implement any other rules you need in your own custom features.
I don't know if you've seen these, but I'm working on a series of developer training videos.