I have almost done this myself. When a driver is turning right, he/she is looking left to see the oncoming traffic he/she is turning into and might well not see a bicylist coming from the right on the wrong side of the road.
Every time I see a child, well anybody really, on a bike riding the wrong way I want to stop and tell them this story, but I don't. Parents, I hope you do tell your children. Policemen/women - please stop these people and tell them how dangerous it is. I actually think it is the most dangerous thing I see people doing around town.