“If you took the issue to small claims or civil court, depending on the amount involved, would a judge find the contract legally enforceable?”
Even if you sign it, it doesn’t matter if the clause in question isn’t legal, and I honestly don’t think in most states a clause forcing you to sell your property back to a prior owner at the same price you purchased it for regardless of your having increased its fair market value is going to be considered valid. If you purchased it, the court doesn’t care if it’s a horse or a house–the OWNER, not the previous owner, is in control of the property and can sell for their price. (Even ones “requiring” you offer the horse back at a price you the NEW owner set are a little dubious, but less likely to wind up in litigation.) Now most people are probably not going to go to court over a horse unless we’re talking at least high five figures, but if you cal it a sale, you can’t expect to demand that the person who took the green bean you bought out of the feed lot and turned them into a solid 3’6" packer with a show record may ONLY ever sell their horse back to you for the $1500 they paid you for it when the fair market value would require at bare minimum adding a zero. If you sold the horse, admit you sold the horse, and didn’t do a long-term lease or a loan, at the end of the day you no longer can dictate what the new owner does.
I mean, if you buy a plot of land with scrub and a single-wide that’s falling apart for $20,000, clear it, build an energy-efficient two-story house with a landscaped yard and a pool, would you be okay signing a contract requiring that if you ever want to sell it, you have to contact the old owner and offer it to them at $20,000 before you can market it? Would you consider that owning the property in the first place? Would a court consider that a sale?
And again, if you have someone sign a contract, a count can simply find it invalid. This has happened in cases where someone signed a non-compete agreement, and the court found the restrictions were illegal (you can’t set unreasonable restrictions, like a two hundred fifty mile radius for your non-compete or a lifetime or unreasonably long time period like twenty or thirty years.)
Sure, the buyer has the option not to buy. But the seller needs to consider that what they’re offering isn’t really a sale at that point. They want to maintain control, though not care and expense, so what they really want is a long-term lease where they refund the fee on termination.