Because it's my horse and when I asked my trainer(who is friends with her) about the release she said that you are supposed to have a tight rein and it didn't seem right to not give the horse their head and let them stretch over the jump at all so I wanted to get a second opinion because I feel she only said it was correct because it was her friend.
Totally reasonable and fair enough. I wasn't sure if you were just at a competition and didn't like someone there.
If this was my horse, I would not be happy. I wouldn't allow them to ride my horse again. I'd also find a new trainer.
If it's a random rider, whatever...
If it's my horse, there's not enough release, it's the wrong bit, and that is a girth sore.
I was just in a situation like this, with a friend, she was also my trainer. I allowed her to use my horse for one student, to do her a favor as she had a horse who died and didn't have a horse for this one student.
They posted videos of her riding, spurring my horse every single stride. I said something, another video was posted, same riding style after we talked.
I moved barns and changed trainers.
It's not the same, but similar. The trainers income apparently is more important than the relationship with you or I.