I watched a kid where I teach go over a speed bump in the parking lot, have his front wheel fall completely off, got the forks dug into the asphalt, go over the bars, land on his face (leaving a six foot bloody skid mark), and knock out ALL of his front teeth. He was completely out for 5 minutes. One week later he is back at school. Three weeks later and the road rash is gone. They put his teeth back in and will wait until December to see if they will grow back into his jaws.

Seeing that makes me check my QR each and every ride. Scared me bad.