I had a problem once with several names being auto-renewed while auto renewal was turned off, but godaddy took care of it for me with no probs. I never use auto renew even if it is a name that I absolutely don't want to lose, just because I want to use coupons to bring the cost down.
That's why they have such an aggressive market. They need it... why? The more people they can get... the more money they will get from people... legally or not.