Absolutely not. Scars do not interfere.

I would also agree mostly with everyone else. If the scar is superficial and it does not effect movement at all, I dont see a problem. The only issue that might arrise is if the buyer is going to show on the line. I have a pony that I have shown on the line and he has a smallish scar on his hind and I know we have been put down because of it. Any scar, bump etc will almost always place you lower in any line shows...Its just the way it is. But how many people show only on the line anyway...Perhaps if you were breeding the animal and want to get a show record....

My horse manages to cover herself in scars. And I swear that my barn is very safe for horses, no barbed wire, no nothing. None of the other horses get scars like she does, she manages to nick herself on trees for crying out loud! If I ever tried to sell her, she would definitely not be considered by anyone looking to show. She has countless superficial scars that don't impede how she works, but they sure are unsightly.

My mare has a huge scar on both sides of left hind fetlock, mercifully no affect to her gaits or soundness. She was inspected, might have been a small deduction for it, but she was still just under premium with both front deviated inward.

I don't actually care... except... across the back could cause an issue with scar tissue. A scar on a joint would cause me pause, if the horse was not in work and sound at the time.

If we held people to the standards we hold horses, 90% of us would not be allowed to breed, or engage in athletic pursuit...