The problem with Great Danes is that they are so friendly. They will protect their families without being trained, but I have an ace in the hole with my Dane therapy dog. I just lean over and whisper in his ear, “What does the mean dog say?” That is his cue to growl. When 175lbs growls people listen. Of course he is wagging his tail so don’t look back there. I haven’t ever done it in public but would if I had to.