The question is not if the authorities will try to tax bitcoins but when. Bitcoin is simply challenging the establishment, and the very liberal approach to the bitcoin in many countries shouldn't be perceived as the governments would put up with the bitcoin forever.
Many believes that Bitcoin at some point will be integrated in the current system at some point, if the bitcoin wish to stand alone, then it is challenging the whole establishment, and the question is if bitcoin is strong enough to take that battle, and if an even bigger part of the society wish to give bitcoin its chance.