Sounds like an opportunity for someone to write some wallet software that will keep track of an individual or business's gains and losses and tax liabilities. Possibly tied to the block chain for auditing purposes. It might be an attempt at a cock block but nothing that can't be worked around. It will be interesting to see what happens in contrast to the UK which has pretty much decided it's a currency (http://www.hmrc.gov.uk/briefs/vat/brief0914.htm). I wonder if London will be taking a lot of BTC business from New York.