Little Tid-Bit on lights going on the back of a helmet.

I always did it! I always put my light on the back of my helmet, b/c I liked people seeing my head blinking as they were driving(I always thought it made me a little more visible).

When I had my bad crash in September, the light came off my helmet, which made my helmet looser and another rider's foot/pedal got UNDER my helmet and left a big cut, which requiered 5 staples. My helmet never came off my head, and their foot did not puncture through the helmet, it literally got hooked under and pushed the helmet.

From now on, I will not wear my light on my helmet b/c if it comes off it leaves your helmet to loose.

(but I used to be the biggest proponent of putting the light there! I even used to work at an LBS and told about putting the light there)