I felt my tenure was likely threatened but the next day I was approached and told that they understood, appreciated, and respected my desire to find a kinder easier way. There has never been a mention of the round pen again.
Wow! Sounds like you're in a really good place!
I have read that backing a horse has successfully been used forever to correct various things like walking off when mounting and correction for not slowing down. Stopping, backing, then proceeding at a walk again. I too have had developmental and behavioral psychology training at the college level and in splitting hairs with you, that is "IMO" technically positive punishment also. Never-the-less, I have tried that on Hondo for walking off nonchalantly after mounting. But Hondo has bunches of personality and is very smart. He knows I am "trying" to punish him and he get really irritated towards me about it.
Yes, backing up in this situation is definitely technically +P. And technically, we can say virtually any 'normal' training we do, based on -R(negative reinforcement, removal of 'pressure'), also necessarily includes +P - because you have to apply an undesirable stimulus to have something to 'remove' as reinforcement. ...Getting carried away & off topic here...
Re Hondo's apparent resentment of the punishment in this situation(aside from the 'resentment' of just not getting his own way
) I think the *intent* and attitude behind what you do also has a huge bearing to a horse. It also has a bearing on the subtle way we do stuff, so I don't know that the horse is at all 'psychic' in that way, just 'listening' to what we don't know we're saying... What's that saying... your thought become your attitude & your attitude becomes your actions...
So anyway, I think mindset is as important as WHAT you do, be that punishment or otherwise & keeping it simple, an animal will do what works & quit doing what doesn't work, so the horse wants to move off, go a certain direction, my attitude about backing is not that I'm punishing the horse for Bad Behaviour, but that I'm preventing
the Bad Behaviour from working - the horse gets what he wants - to move off towards home, or whatever - when he does it in a way I like, but it doesn't work for him to lug, prance... whatever.
And all I've got to say to the rest of your post, sounds like Hondo is an extremely lucky horse to have you!