"We cleaned it up"

I came home from several errands and found Matthew & Jamie coming downstairs as I arrived. (Grandma & Benjamin were in the living room.) The first thing out of Matthew's mouth was, "We cleaned it up." Meanwhile, Jamie had something concealed behind his back.

I thought to myself, gee, this can't be good, so I asked what Matthew was talking about and pulled Jamie's hand out to reveal a paintbrush. Those little sneaks had taken a small model aurplane kit that Matthew had gotten as a prize and painted it in their room, on the floor, without any protection on the carpet (or permission to do it at all, for that matter). I was shocked that the mess wasn't any worse than it was, but we had to lay down a few rules about things (yet again).