Actually I'm inclined to agree with Lisa. It's 'easy' enough to get a unsuspecting horse on a trailer for the first time. It's not the first time that's the problem it's every time after that. Either the animals enjoy the activity, have developed a tolerance for it because of some awesome positive reward, because like Lisa I cannot fathom how you would persuade a horse to do that. If you use beatings you would have to beat it every time. Or have some form of threat ready that it couldn't avoid. Doesn't make sense.

Does it look unnatural and scary? Heck yeah? Dangerous for the horse? Absolutely! But the question is...is it?