Well not knowing how to tax something never stopped Gov't before. In Massachusetts I have heard one is supposed to declare income made through illegal means in addition to anything one buys out of state or over the internet. They also sell protection money. If you don't want to take the time to declare everything made this way you can just pay a fee based on your income...a get out of jail free card. No questions asked if perhaps something (ahem) should turn up. ;-)
Now, that's a slander on MA -- they only had that line on the tax form for two years! (I can't even imagine how much it brought in!)