Sounds like you almost get it. The honest seller says “broken truss rod. As is.” Sellers often encourage questions being asked. IF there’s a deal breaker regarding the condition and it’s not obvious by image or seller description, ask!How do you know if the seller is reputable? If the seller is reputable, it should be listed as "broken truss rod" or whatever. There is no reason for a reputable seller to list anything with "as-is". It's just an attempt to push the responsibility onto the buyer to find out any issues before they buy. If they don't ask the right question, "Hey, I said as-is in the ad, sorry."
Used isn’t for everyone nor a obligation. So you don’t like what you see psss it up. Yes, PayPal overrides sellers personal policies, but that’s supposed to be for if you are really scammed. NOT feeling ambivalent over a done deal.
Here’s a fun tip to lighten anyone’s day, particular when you have bad photos to work with and minimal descriptions but a set in place return policy (such as on Guitar Centers cite): set your expectations a little low. Don’t expect something broken outright, but be prepared if more set up work is needed or there mild cosmetic issues. That way, when it arrives and doesn’t have much of that if any, you’ll feel so much better. Is this relevant to As Is deals? No, but I thought I’d share.