I ran across this video a while ago on what can happen to you if you don't pay your taxes. At some point during your Bitcoin career, the cryptocoin will be converted to fiat and that's how they will catch you.
https://www.youtube.com/watch?v=hf2fNEUPjQwYeah once we convert Bitcoin into fiat money taxes will automatically applied. Our local exchanges here in my country are regulated and that is how they tax our funds. I am not against tax and to be honest we cannot evade from it though it will also be helpful to our economy too. Tax is everywhere and that is how we live life from now on.