Inventing for lazy parents

I just saw an ad for some special paint marker things for kids. They markers only write on "special"paper. Not anywhere else. The ad showed a 2ish year old writing on a white wall. Then it panned out to show the special paper and how it doesn't harm the wall all the while the "mother" beams with pride at the "art". When did it get so freaking hard to kick your kid's ass for doing something stupid like writing on a wall that an engineer had to develop invisible paint?

Feh. I can't wait until that same rat finds one of daddy's sharpies and pastes the side of his car with it.