Ebay has several informational pages on this topic, all of which basically say that they do not support the trade of stolen or illegal goods but if it happens it's between the buyer and police. They offer help, though, which seems limited to providing whatever information they may have to the police..
The sale of stolen property is not allowed on eBay.
www.ebay.com
Customers - Security Center
pages.ebay.com
As mentioned before, the buyer of stolen goods, when they are seized and/or returned to the ir rightful owner leaves the buyer in a financial loss. Civil lawsuits, of course, could be filed but good luck with that. It is likely that some evidence of direct complicity in the illegal aspects of the deal would be needed to prevail. If they, eBay or the seller, were unaware that the goods were stolen then it seems that the unknowing buyer gets stuck with the loss.