Revamped the require-client-classes idea.
Obviously the require-client-classes feature lacks adoption. My idea is to replace it with a simpler feature which is almost as powerful but more uniform.
Currently we have for host reservations "client-classes" which adds each class of the list to queries matching the reservation. I propose to rename it to "add-client-classes" to avoid confusion with guards and to apply it to scopes where require-client-classes where defined.
The "only-if-required" flag must be changed too: perhaps the original idea of a late evaluation flag should be considered again?