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
You are right it would really depend on a certain country if they do have actions when it comes on bitcoin income and now politicians on my place are now advising the citizens that they should avoid bitcoin if they dont like to lose up money and for those people who doesnt have idea on what bitcoin is for sure they would really easily believe on what those politicians say but as a bitcoin user they are just trying to lure away people since they do know the possible effects if most or majority of citizens would engage to bitcoin.