In order to avoid paying tax, I use online exchangers. They can be used to send the Fiat on any account without registration. In this case you will not track and you can do any in-store purchase without using your Bank account. It seems to me that bitcoin was conceived in order not to interfere with the government and therefore I consider myself free from tax liabilities.
It's depend on their government whenever they have legalize and apply tax or not.
Meanwhile my government still not legalize yet so no one forcing me to explain bitcoin as my income. They just forbid bitcoin as main transaction because bitcoin can be use for criminal things