This is exactly how a home inspection provision would work in a P&S contract. You don't get the right to deduct from the purchase price for things found in the inspection--you get the right to walk away.
Practically speaking, the seller is going to make a price accommodation or fix the issue, because if you walk then the next buyer is bound to find the same issue. Even more, now the seller knows about the issue and has to consider whether he'd need to disclose it to a future buyer.
Ever see this Gemini for sale? The Slapdash | No Fixed Address