Do these really work? We adopted a year old dog almost 2 weeks ago. For the most part she seems potty trained, but she has had a couple of accidents since we got her. This is complicated by the fact she went into heat 2 days after we got her so she is wearing doggie underwear, and clean up is quite disgusting. If she is showing a sign, we aren't spotting it. She does not bark or whimper at all (seriously in 2 weeks she has barked once). She seems like a smart dog, but I have never used something like the bells. Are they something easy to train? Do dogs with strong chewing drives, chew the bells? Any tips from people that have BTDT?