The worst part for inexperienced riders of any age is the lack of understanding regarding counter-steering, and target fixation. I saw a guy on a brand new harley (he had just picked it up that morning, at the start of the charity ride, which started out from the harley dealership) who hadn't ridden before (and he was proud of the fact!) literally ride his bike directly into oncoming traffic. He paniced when we were riding over a bridge with a metal grate surface, and the vibration, combined with the weaving patterns just freaked the guy out: He was looking at the oncoming trafic, and he began to veer towards it. Luckily, he was able to stop, and the oncoming cars were able to avoid him. An older couple had the wife (riding pillion) and this rider swap positions, and they broke from the crowd, and drove him back to the dealership.
Mark