I really meant what I could get away with after doing an AB roll?
Block.
Thing is, you can simply punish rolls in their recovery, easiest way to hit that is to spam like cr.B, if you don't roll they'll hit you in front, if you do roll, they'll turn around and hit you in roll recovery and punish you bigtime.
They could also go for a meaty close C, sweep etc.
Needless to say, AB Rolling without knowing exactly why you are doing it, is a really really bad idea.
So when do you AB roll? when you know for sure that your opponent will do a move, that has such bad recovery that he will take longer than you to recovery. Then you can punish with your best punish.
If you meant guard cancel rolling. You're completely safe to attacks and throws when you do that, but when your opponent sees it coming, he can still meaty you on the recovery. In that case the answer is once again "block", but could also be "dragon punch" or "reversal throw", but that's really disrespectful, and against good players you won't get away with that more than once.