Yes, you have some BO's that are dishonest, some boarders who are dishonest, some people who ride without permission, none of this is good. And then occasionally you get the nutball owner who asks you to ride her horse, and then tells everyone else that she didn't and that you screwed her horse up. I had a boarder that was going to be out of town for a couple weeks, and she sought me out at the barn to ask me to ride her TB while she was away, and told me exactly what she wanted done with him. I noticed that he was having some problems with his vision on one side and so I informed his owner that she needed to have the vet check his eyesight, and she went nuts on me, telling everyone that I had snuck and ridden him while she was gone and had made him jumpy, spooky, blah blah blah. I thankfully had a witness that overheard her ask me to ride. Finally she got the vet out and he told her her horse was almost blind on that side. She actually argued with him, and told him that it couldn't be that, that I had screwed him up. Needless to say, she was given notice by the BO at that point.
"Keep a leg on each side and your mind in the middle"