I would not agree that freedoms are actually increasing, especially financial ones were in many countries everything is already under the full control of Big Brother. The whole set of laws introduced by the Americans after the attack 9/11 actually allowed not only the USA to become a totally controlled state, but the pressure from the Americans on other countries is constantly increasing to do the same.
If you think you are free then you haven't been paying attention. Even the things we know about are horrendous. The "EARN IT" bill allows the government to stick their noses in to encrypted data. The recently proposed "Lawful Access to Encrypted Data Act" will force companies to build backdoors in to all their software and allow the government to read all your encrypted data. The Snowden leaks and the NSA mass surveillance program is incredibly invasive, and is only the tip of the iceberg. Think of all the far worse things going on behind closed doors that we don't know about. We live in a surveillance state.
I just think that at this point, in the "first world" countries, no BTCs were seized just because they were "dirty", ever. CMIIW, please.
Not by the police/feds/government, as far as I am aware, but centralized exchanges seize coins and freeze accounts on a daily basis if they don't like where the coins have come from (and sometimes if they don't like where you've be sending other coins after you've withdrawn them).