My horse is a coming 4th level dressage mare. She has just been, well, different recently ( not on the same "channel" she usually is). Unlike the real DQs, I have to work and am pretty much the only person who doesn't come during the day. So I just found out that this horseless lady who's only ridden a little huntseat & has awful hands who I thought was taking lessons on the BO's horse has been using mine. Didn't know whether to believe it or not, so checked my saddle, and my stirrup leathers are not where they should be and I have a nice, long scratch on the seat... There's a clinic tomorrow that I'll be "missing" and I get the impression that she'll be riding my horse in the clinic (that I can't attend because of "work"). Must be why her mane & taile were shampooed when I came today- funny, I don't pay for that. So what should I do when I show up tomorrow during this clinic? What is my legal recourse? I have spent thousands on training that is being untrained. My inclination is to show up with my trailer... Can I sue her, the BO or both maybe? I've worked hard to develop my horse- this is theft.