Our Government here will always question people who become rich instantly, sometimes they will relate all the wealth to drugs and smuggling so they can send us to jail for a questionable wealth and not paying taxes. they will do background checking, even if they dont find any illegal activities we did they still think that we do illegal. What if I become rich because of BTC do you think they will believe if I say that its bitcoin that making me rich? How will I explained to them?
Well, practically if they don't have evidences that you do drugs or something like that, somethig illegaly , they can't put you in jail. maybe only if online trading are something illegal in your country i think ,but all you can do is paying your taxes to the state an then , try to explain to them how this works, or try talking about how the technology of these years has advanced.Really you it can't anything happen to you if they don't have a proof that you've done something illegaly.