1) Scammer can file a claim that he never received the item, but just an empty package. Oldest trick in the book of ebay scams.
2) It's rare, but there's a small chance the package gets lost. You're responsible for lost packages. Sure you can send out a replacement, but they could potentially win on the basis that it took too long to arrive.
3) Scammer can dispute that the item was not as described. If you send an error penny, they can claim it's a normal penny. There are many people that collect numismatic coins, it's very easy to prove that the coin is not a valuable error coin.
^ What he said, lol
I'll throw in my 2 bits...
1. I will warn that this method is through local bitcoins, not eBay. eBay will let the buyer win for almost anything. PayPal however has very limited coverage but it is their "seller guarantee" and you must make sure that the address on the ID from buyer, name match the PayPal account. Then you just click to ship item right in PayPal and it will fill in the address. They can't claim it didn't arrive, they signed for it. Now, also it is an important step to include on the invoice. RARE COIN. I cannot accept refunds and returns once you have accepted the document. Now, the other thing is... keep your selling limits low to prevent a huge loss if they figure something out. Usually what these guys do is steal a PayPal (won't work here as you will get ID) or they do a ton of trx in a few days and then claim unauthorized... Well, they won't be able to with your sale. I had a folder ready... copy of invoice, copy of their ID. When PayPal sent me the chargeback email, I went straight to PayPal and uploaded... ID, Invoice, and delievry confirmation... all 4 times the money was back in my accoount same day. It cannot be unauthorized in this case and even if they convince their bank or PayPal... PayPal owes you.
2. You are sending signature required Priority Mail and all it contains is a penny or dime. 1 in a few thousand might get lost but you would have a case against USPS for your "error" coin. Remember, the person paid more for instant delivery too. If they paid for 3 day (half mine did) you are fine because you lose no btc.
3. I never said use ebay so go read my method again. With PayPal, you are covered here. Your claim is he replaced the error with a plain penny and you were nervous he might try something which is why you did signature required and why you put on the invoice... no returns or refunds once item has been turned over into his hands. He would have to open the box with USPS at door and then decline it... so you just don't release the btc.