I was working with Riley yesterday, and we were trying to learn how to leave a piece of cheese in front of him until I say the command to let him take it. I was under the impression that I should not release him from his "wait" command until he began to ignore the treat. Well, he eventually did this, and he started to um, clean himself...so I released him and he took the treat. I thought absolutely nothing of this, but the next time we tried and I said "wait," he IMMEDIATELY turned around and started licking himself again. Wow, it's funny how incredibly smart they are and how HE made the connection between licking himself and getting the treat before I even did. We are now working on a little different method. :
As a side note, I'm not sure why it was implied to you that you should wait until your dog begins to ignore the treat before you "release" him. Maybe there is a good reason for that that I am not aware of, but to me, you want to opposite. When you are teaching stays, it seems to me that you want the dogs focus, you don't want to lose it.