note that sheer force life orb works without damage, and does similar with choice items and assault vest. this is because sheer force blocks secondary effects, like only being able to use damaging moves for assault vest.
Edit: Really? I got that from a trusty source! Ugh, I feel like an idiot.
P.S. I told my friend, a competitive battler since the beginning, about this and he said he thought that sheer force did it, too. Maybe this only worked in previous gens, but I don't know, nor can I test this.