What sad people they are Gary, fancy telling on somebody in a buffet restaurant, they need to get a life!
I don't think I've ever been to a buffet kind of restaurant myself, but if I eat out say at a chinese, any left over meat I bring home from there for the cats. I used to for Jack and I do for Xavi.
If you've paid to have your meal and it's a buffet surely you are allowed to take as much as you want? Obviously within reason. Plus some people really take the mickey and pile up their plates and leave most of it, which is worst?!
You are certainly not a criminal Gary for thinking of your animals and saving them a treat.
And yeah I'd take my business elsewhere, then just in case when you do find a new place, drop it in the conversation if you could take a little extra home for your cats...most people would say okay.