Generally the policies of eBay and Paypal are heavily biased in favour of the buyer. They want to encourage people to buy and to make it a "safe" environment for them to do so. The buyer can turn around and say that you never shipped them the item and Paypal will refund them the money with next to no questions asked. It will be your onus to prove that the item was sent, was correctly shipped and that they actually signed for it. Unless its an exceptionally high value item, you'll waste more time in paperwork and gathering evidence that its easier and cheaper to write it off.

This is one of the reasons why a lot of people I know that used to sell on eBay have given up on it. They were getting regularly scammed and eBay + Paypal wouldn't do a thing. It is too easy to create another account and continue scamming.