Seriously having given Chums idea thought I think it needed a complete over haul.
So let's stream line it.
So here is the game. Create a template that tames pets to leave them outside a person's doorway in order for the owner of the house to flag grey making them attackable, killable,able to be stolen from etc. when they try to get another key or enter their residence if they kill the creatures to do so
(It doesn't have to be cats it can be any tameable creature...Imps would be spectacular)
If you are busy macroing like I am this is a perfect waste of time

So try to be creative...