^^ I personally know a horse dealer that has done that in the past to someone else I know.
The horse, when not drugged, would rear and flip when you tried tacking it up.
She also has a policy that if you're interested in a horse she tells you the day and time to be out there.
I found that out after looking at horses she had for sale. Thankfully I didn't buy a horse from her (they were way overpriced too)
Got2Gallop, I thought the same thing! If he's a farrier, trim the horse so when people come to look at her, it doesn't turn them off.