Well, in all fairness, as a seller you're not totally effed if someone tries to do a chargeback on you. You have an equal right to dispute that chargeback and provide proof of shipment and that's the same reason why many sellers will only ship to Paypal confirmed addresses.
Also, to those who think eBay's a total risk, scary, etc... remember that it's much more likely for someone with a negative experience to post that on a bb such as this. The *vast* majority of eBay auctions go smoothly and are without fraud. Buy with a CC, check feedback, and use any buyer protections/insurances that are available to you. And if it's too good to be true, STEP AWAY FROM THE INTERNET!!!