If the government forces your exchange to release all your information and logs, then the exchange will kindly cooperate and supply the government with everything they need.
That is the exact reason as to why I always mix the coins that I withdraw from any exchange. I even mix the coins that I withdraw from BTC-E even though I am not verified with my private data there. I do everything to avoid the government from potentially getting any information about me and my holdings.
Governments asking the exchanges for data about certain people may seem to be a very extreme measure, but I don't take any risks. I will do everything to keep my coins outside the reach of the government and its ridiculous tax structure. They already tax people so heavily, so why should we allow them to gain more from us? I always say; Better safe than sorry.