Good question. Early on when I was trying to create a milli-cent currency for subscription buying of content from a website we wondered if we offered a refund for our digital cash tokens if we'd get in trouble for it.

As it turned out the Digi-cash folks had all the patents and were being real dicks about licensing so we never got to test the question.

I can absolutely predict that if you can buy several hundred thousand dollars worth of bitcoins from person X, and then go to persons P, Q, R, ... Z and redeeem them back for cash, that the authorities will shut down that sort of thing quite quickly.