just a point to avoid jumping to conclusions: she never said if she did or didn't ask permission. The barn owner may have approved of her setting the cameras up, and therefore wouldn't be offended. It may be a big barn, a barn where it's hard to keep track of what's going on, who knows. It sounds like she was just concerned for her horse's safety...I do understand why somebody might take offense to it if it was in their barn without their knowledge but I don't think it sounds like it was done with ill-intent.
A horse is the projection of peoples' views about themselves--strong, powerful, beautiful--and it has the capability of giving us escape from our mundane existance.