15mo old only signs when doing naughty things

This isn't necessarily a problem, just funny in my opinion lol. 15mo will only sign "please" and "more" when doing toddler shenanigans. Ask him nicely not to mess with grandpas tv (turning it off and on), stopping him from playing with dog food, unrolling a whole roll of toilet paper, and he will look at me and sign please so perfectly! I say "I see you signing please, but we still can't play with ___" and redirect him, etc. He won't sign please and more doing anything else haha I just think it's interesting.