Our entire relationship with dogs and horses is literally, de facto, B&D. We put them in harnesses and collars and walk them on leads, and they are subjected to training in obedience. Occasionally, we even muzzle them. Adding more of the same, for no practical reason, would seem deranged, and I would inquire as to whether or not someone that did so ought to be considered for long-term in-patient psychiatric care.
Tying up a human being sounds entertaining. Being tied up also sounds entertaining. I think that the fantasy of being or pretending to be as much under another human being's control as one's animals is a natural fantasy for many zoos. If one is attracted to a horse in full leather tack, then one cannot be blamed for thinking that oneself would also look good in the same. It is not particularly of interest to me, but I cannot find fault in it if the situation is safe and comfortable for all parties involved.
I am generally against S&M. Even when it is being done to humans, I just don't see the appeal. I disagree with the contention that something ought to be done to someone just because they would agree to let you do it. With my romantic partners, I think about the overall gestalt of their psychological and physical health, not just about their current wishes. Sometimes, it is best to simply say no.
