Smoke-Free Restrooms

In any circumstances, what can you do with restroom smoking? There's no way to tell when one's doing it and you cant surveillance them all. Smoking is a habit that is hard to break as well as catch in school or public restrooms. Really, I have no solution to the problem as far as smoking unless the goverment or someone who is like head of the board of education gets a hold to something like a new smoking detector.