Gox is currently in the process of running batch programs to transfer all BTC within there domain outside. They are not currently allowing transactions from a MtGox bitcoin wallet to an external bitcoin address. This is so that users can continue to see false information as to their balances while they pilfer the loot. They will be posting shortly that due to a technical problem beyond their control all is lost. They are currently allowing transfers of BTC between Gox addresses, as those are fake and within their control. They are also allowing currency withdrawals (Yen, Euro, etc.) as those are government backed currencies and stealing those will get you jailed. Disappearing BTC is not new, and not a single person has ever been arrested for pilfering BTC and never will. So where is BTC going, I'll tell you, it is going, going, gone baby, and the MTGox people are already on a plane to someplace nice and warm 
In countries where Bitcoin is considered a commodity, its theft most certainly can and will be prosecuted. Successfully prosecuted is another story.
I think the real question is whether bitcoins can actually be owned. A private key just gives you access to a particular wallet, and not even exclusive access (for instance, who owns the "password" brain wallet?).