Ever been grossed out, a la Seinfeld, by someone who visits the bathroom but doesn’t seem to know what washbasins are for? You need the iGene: 

i-Gene [sic] is designed for washrooms or areas where hand hygiene is critical. It detects movement and after a given period of time (pre-delay setting) will play the following real voice message. “Please wash your hands before leaving this area.”

Usually, I’m not for any kind of nanny-state type stuff, but it does amaze me how few people (read: men) wash their hands after a spell in the bathroom. Now I’m up for not just installing an iGene in every bathroom but of having anti-bacterial handgel guns on either side of the door to fire at miscreants as they try to sneak out without performing any manual cleansing.

Of course, the solution is to fit decent hand dryers so that people a) don’t have to calculate the value of hygiene against the possibility of catching a cold from damp hands and b) can have fun drying their hands in a warm and powerful jet.

The other move would be to either install automatic doors so you don’t have to put your clean hands on a doorknob used by all the non-handwashing Poppys or to at least put a bin outside the bathroom so clean-minded folk have somewhere to discard the paper towel they have to use to open the door to avoid getting all bacterial again.