I was reading the user klee who was hacked of 1170 bitcoins (apparently he got some back from the thief) and the issue to me was if bitcoin is like stolen cash or stolen goods? If
BTC is like stolen cash, which is considered "fungible", then there's no legal requirement it be returned, unless the owner knew it was stolen (that's why banks will mark bank robber money with red dye bombs). By contrast, stolen goods are must be returned by law, even if the buyer had no reason to know the goods were stolen.
If you read the below, due to an US IRS ruling, it is believed that bitcoins are considered "goods" so stolen
BTC can be traced and returned to the rightful owner, if the theft was in the USA. But there has not yet been a court ruling to this effect. However, due to the blockchain tracing all transactions, I bet some judge rules that
BTC are more like non-fungible goods than fungible currency.
TonyT
http://www.theguardian.com/technology/2014/mar/31/bitcoin-legally-property-irs-currencyAdam Levitin is a law professor at Georgetown University, and he believes that the ruling means that bitcoin can never be treated as "fungible" – a term from economics which refers to the fact that particular instances of a good are interchangeable. So, for instance, crude oil is fungible, because if a trader buys a gallon of it, they don't care which gallon they get. Fine art is not fungible, because which work they get matters a huge amount.
But the really interesting problems will come when a similar treatment is applied to criminal law.
In many legal systems, receipt of stolen property is treated very differently to receipt of stolen money. If a pawn shop accepts a stolen bike, its operators are expected to return it to its rightful owner if discovered, without reward. If a coffee shop takes a stolen fiver, it can keep it.
Until someone brings a case to court, it's impossible to say definitively which version would happen with bitcoin. But the IRS ruling suggests that, in America at least, it could be the former.
In other words, if you think the hassle of having to file taxes on your bitcoin is bad, just wait til the shop you're spending them in has to check to make sure they aren't stolen before you can make a purchase at all.