Does anyone have experience with training dogs not to bark when new people are around? Sally is actually well-disciplined but has started to bark at people when they come over. She'll go into sit and down, and still bark. I've tried to do what I did when she used to bark at the vacuum cleaner which was just to block her way to it and make her lay down, which worked great... but it doesn't work with people. I'm looking for any advice!