Originally Posted by Rowan
Looking over the shoulder is a cycling skill that must still be cultivated and maintained, mirror or not, I believe.
Agreed.
The ability to look over your shoulder is a very important skill because the mirror has blind spots and you don't want to just "dart" out of your position. There are going to be time when you have to cross a four lane road with no lights and scan for all traffic. It's at this point (where you must take your eyes off the wheel) that your front wheel can hit a pot hole or rut and jar you off the handlebar. This happened to me so you always need to be aware of this danger.