Oh yes, absolutely! The only time I didn't enforce it is this last episode w/Yodie and Puddy. I had to put Puddy in her room to isolate her when Yodie picked on her but that's because Puddy's so fragile right now. But ordinarily, the offender gets put in a carrier and they don't like it one bit but they get the message. People are always trying to tell me that cats aren't that smart. Gimme a break! Clearly they aren't cat owners.