That's not nessesarily true often dog do better if they are trained in bitework before or during the time they learn OB. It can create conflict in the dog if his whole life he's lost every conflict he's had with a man during OB training especially those things that require compulsion. Especially with handler sensitive dogs. You don't want the dog being worried about getting in trouble with the handler rather than focusing on the decoy. Those dogs do have to be well contained during that period.