We've never put ours in a cabinet, as that takes up way too much space in the cabinets that we need for other things. Even on rigs that have a cabinet specifically designed for such, that cabinet is always used for something else that needs to go there.
Sooo, in nearly every rig I've owned, we put the trash can under the dinette when on the road. When parked, it goes somewhere else (typically in hallway across from the kitchen).
I think, this is one of those things that you're going to get a different answer, opinion from everyone. There really is no one single answer to this.