Here's an idea. If you can't change his mind, at least have him buy a nylon halter with a breakaway crownpiece that will break if it gets caught. It doesn't work all the time, but it works most of the time, and that's what's important.
As for pictures....you probably won't get many people posting those on here as most of us would be more concerned with freeing the horse than running inside and grabbing the camera LOL, but if you want a story, here's one for ya:
I bought a Paint Clydesdale gelding a year ago who'd been a pet his entire life. He walked all over most people, did what he pleased, etc, but he really respected his owner because when he was a foal, the owner was working in the barn and the mare and foal were running around playing in the pasture. The foal had a halter on and slipped under the chain link fence that was temporarily surrounding the pasture until a better fence could be afforded. He was struggling because his halter was caught and he couldn't get up from under the fence. Panicking. The mare ran in the barn and started bucking, rearing, and running around to get the man's attention. After 5 minutes he went to see what was the matter, and he found the foal, who was amazingly unharmed.