what if one of those transactions was for cash? no way of knowing if that final withdrawal from gox was the person who used those school computers. alternativ

what if one of those transactions was for cash? no way of knowing if that final withdrawal from gox was the person who used those school computers. alternatively, what about exchanging between multiple cryptocurrencies? more and more pop up every day. there are unregulated exchanges that let you do that and the only bitcoin transaction would be the deposit into the exchange. the withdrawal could be in any random form (including wow gold or second life linden dollars). the possibilities are only limited to the person's imagination.