I gave Ember an old cell phone to play with. While we were in the kitchen and she was hanging out by me while I did the dishes I gave her a piece of granola bar.
A little while later I came out into the front room to find the granola bar being painted on the cell phone.
See, Payson spots Ember doing something naughty (she was rubbing the granola bar onto there first) and breaks out into a huge grin and joins in. He may know something is wrong and not do it on his own but when he sees Ember do it it’s like permission to be naughty, too.