I have seen many trainers do all sorts of wild things with clients. Mostly those that haven’t properly studied human movement. Various modifications exist in exercise, some I THOUGHT were a little over the top, but when performed correctly are safely challenging the exerciser from a different angle. Many years ago, I about flipped when I wittnessed a curtsy lunge; I do them regularly in my own routines now. Usually, if the form isn’t there, then its probably too soon for that advanced modification. If it cannot be done with good form, it just shouldn’t be done as a TRAINING technique.