Actually I think that sort of thing happens for another reason entirely. You see, it is normal for the dog to consider only one member of the family the Alpha - although, if he is trained correctly, he'll still know he's in the base of the command chain and obey everyone. So what I'm saying here is that even with the woman doing things wrongly, the boxer should obey the man.
The problem here, I would bet, is that they let the dog be trained by someone else while they themselves got no training, so to speak. The owners need to learn how to manage their dog, not just let someone else do it for them - othewise what will happen is that the dog will only obey the trainer. The best classes are those in which the trainer gives orientation and the owners themselves teach their own dogs, so that their dogs learn who their master is in the process and the owners learn how to teach properly.
