I allow chasing, liplocking, and tail slapping in my tank. As long as no one is being injured, hiding all the time , and not eating it's allowed in my tank. This could be a double edged sword because depending on fish selection and tankmates it could escalate very quickly into something much much worse. These fish can be big and mean and that's why selecting tankmates is so important.
There must be a reason your asking so what are you seeing? If your keeping Rainbow's I dont normally see them overly aggressive.