I do bus my table in CL's. I think the problem is the fact that it is not always set up in a way to enourage people to do that or even inform them that it would be nice if they did.

Example: at a FS Marriott in Cincinnati I was running around with a dirty plate in my hands for a while (I must have looked retarded) until I found a hidden brown tray. (It wasn't literally hidden, but it was out of sight - next to and sort of behind the desk where the attendant was, very close to the door. As you looked either the desk or the door caught your eye leaving the brown tray in the background.) There were no other plates on the tray and there was no sign of any kind indicating its purpose. I almost put the plate back on the table until I thought that the brown tray must be it. Especially with the morning rush, I couldn't help thinking that if the tray had been more visible or if some sort of small and polite sign were somehow posted then I'm sure more people would bus their tables.