[halostatue]

IMO, it was a lost phone right up to the point that the finder decided to sell it, at which point, it became theft. If he decided to keep the phone as a trophy, but not sell it, he would have been on the wrong side of the law, but a) we never would have known about it, and b) it's unlikely someone would have cared enough to track down the finder.

I think that most jurisdictions would consider finding something and not making a good-faith attempt to return it to be indistinguishable from outright theft. Sale of such an item would be hard to justify under any circumstances. (IIRC, airlines sell lost luggage in auctions, but there is a suitably long time permitted for the flyer to claim their lost luggage.)