Sounds like she's got a career as an Evil Easter Bunny ahead of her.
A couple of years ago, my younger grandson, who's now four, got extremely pissed off with my daughter, because she wouldn't let him sleep in their bed. Yelled, played up, the lot, but eventually accepted that he'd have to sleep in his own bed, as usual. Some time later that evening, water started coming through the lounge ceiling. The little bugger had only got up, put the plug in the bathroom basin, turned on the tap, then gone back to bed!
He's never done it again!
A lot of this behaviour derives from soft drinks.
MG