Agree with everyone .... especially agree with Rocco Boy, haha.
Time to bring out the bee-atch talk if this moron doesn't respond to you asking her nicely.
She has ZERO right to touch or handle your horse. It is not her horse and she does not have permission to touch him.
I'd edit your sign on his stall too, if I were you. Something along the lines of:
"Please do not handle my horse because of his biting problem ..... and that means JANE DOE you are not allowed to touch my horse. Get away from him!!"
It'll be embarrassing to her to have her name on the sign, and everyone's going to know it.
You've already tried asking her nicely to not touch your horse. Now she has to pay the price of not listening to you.
Some people are just dense.
∞•*˚ Βгįťţαňγ ˚*•∞
It is not enough to know how to ride; one must know how to fall.