See thats messed up.. kids and sidwalk chalk go hand in hand.. and it hurts NO ONE.
The old farts should learn to enjoy the artwork and be happy the kids aren't spray painting their doors or throwing rocks through windows.
How does your garage fare through winter? .. you guys get a decent amount of snow up there, when it melts off and re-freezes doesn't your garage floor turn into a ice skating rink?
Thats dangerous too.