I recently had a chargeback from a scammer on ebay.

It worked like this.

1: I got notice of the chargeback and the funds in my paypal account were put on hold
2: I uploaded the tracking information to paypal showing that I did indeed ship the item
3: 10 days later the money was returned to me and all was fine.

If that happens.. its just scammers using stolen credit cards and you are covered.

But... There is a different kind of scam which is much worse.
Scammer buys the item. Then opens a case with ebay saying the item is broken or not as described.
You are required to tell the buyer to send it back for a refund.
The buyer mails you back an empty box.
Ebay still forces you to refund the money.