Only if you are 100% sure that the seller has stolen it or got it unlawfully or you got it for an amazing low price that you should have known it's unlawful. But there's no way you could know that in a shop like environment as it's sold openly. Similair situation would be buying a stolen bike from a bike shop. You can never imagine that a shopkeeper is selling stolen goods or you don't have to know that according to the law. If the initial rightful owner were to reclaim his bike, he would fail but he could always receive a compensation from the one who stole his bike. But he is not the rightful owner of the bike anymore as the buyer is. Btw sorry my english sucks, I know. I'm trying to read more books to improve it.