This may be a long/complicated story, so if you have any questions, feel free to ask.
My barn is leased by my trainer. She rents out a block of stalls to another trainer who has about 10 boarders(number may be off, not important to the story). I’ll call this trainer Molly. Molly has a young daughter, I believe 4 or 5 maybe, who comes to the barn with Molly sometimes and loves to give the horses treats/brush them/etc.
My horse that I’m currently leasing is a total packer, teaches me everything, and is very sweet. She’s under 16 hands and a kid learned on her before I leased her.
Anyway, back in the winter, most of my trainer’s clients(including her) got COVID. She made the decision to shut her business down for two weeks to ensure everyone was safe . However, I believe Molly was still running her business/teaching lessons to some clients who weren’t exposed. Two days before our barn quarantine was up, I was browsing my barn’s facebook page, as well as Molly’s business page. However, a certain photo on Molly’s page stopped me. I zoomed in closer and I knew it was my horse. Same facial marking, same socks, etc. However, Molly’s young daughter was riding her, with one of the assistant trainer(who was being paid to ride my horse during quarantine)'s for Molly’s barn leading her. I was a bit taken back by the photo and kept scrolling on. There were more photos of Molly’s daughter on my horse, being lead by the assistant trainer. I knew they weren’t from the same day, though, because Molly’s daughter was wearing different clothing, different lead rope, different saddlepad, etc. Now, I understand that Molly’s daughter didn’t have a pony/horse to learn on, and she really wants to learn, but to me, that’s no excuse. I am not a charity and I pay for the horse. It’s out of my pocket, not Molly’s. If something were to happen(I know it was only a leadline lesson, but my horse spooks a lot, and a 4-year-old would not be able to stay on if she got scared of something), but if an accident happened or my horse were hurt, the question would arise, “Why was she on the horse?”. In my lease contract, it specifically says that only me, family members, and trainers are allowed to ride the horse. The lessors could possibly take her away from me, or if she got hurt, I would have to pay for vet bills. Molly never asked me, I found out from the photos. They have never told me to this day, I doubt that they know that I know. I know that nothing happened, but if it happens again, what should i do??