In my country, you can't even find a place where "Bitcoin" is written on something, so i don't think if the government would need to be concerned with anything related to bitcoin right now. Maybe if in future bitcoin overtakes the country and is found everywhere then maybe the government will start tracking the incomes of people coming out of it, but that doesn't seem to be happening very soon. So i don't really declare my bitcoin income and i don't even need to do that.