The paranoia is strong with this one.
Just because you're paranoid doesn't mean they aren't after you.
- Joseph Heller
Seriously though...., don't dismiss this as a risk. If in a couple years Bitcoin rises 50x from its current value, just like it did in that past couple years, the response by the State will likely be to round up those responsible. And the surveillance they do now just helps them justify their case. Did a trade on LocalBitcoins? That might be enough to hold a person for a few weeks on suspicion of operating as a money transmitter without a license. How would "they" prove it"? Well, LocalBitcoins sends confirmation of each trade, in clear text, to your e-mail. Hinted that you might like to light up? Well, even if ten thousand people just like you in your part of town do the same thing what if you happened to be the one that got the knock on the door? Coincidence? Nope!
We know the the tools necessary (Tor, GPG, mixers, shared send, etc.) but we (or most of us, myself included) don't use them.
We are doing nothing to prepare for the day they go on the offensive with regard to Bitcoin.
I don't expect that 'ex post facto' principles will be tossed out the window readily. There would be so much collateral damage that it would be a poor strategy decision in most scenerios. Bitcoin is clearly to most not illegal now, and although there is a much higher percentage of blatantly criminal activity in the ecosystem, it is not dominant enough that a majority of those effected by a cross-the-board crack-down would be guilty. And the userbase is growing daily. Many people would have a friend or relative effected if some sort of totalitarian abuse happened across the board and out of the blue.
I think it is almost a certainty clear to all by now that there are individual 'dossiers' kept on every citizen of the US (and probably of the world), and that a variety of algorithms constantly sift through the every increasing collection of data. It is very probable that individuals are tagged with all sorts of flags, and that different flags are used to select different types of analytic regimes. I would be completely surprised if an effort to identify persons with an interest in Bitcoin are not underway and do not produce certain kinds of flags. If there comes a point when an attempt to crack down on Bitcoin is chosen as a policy, I would not be surprised at all to see those with a history of involvement with Bitcoin be readily identified. Whether it would result in a the old-school 'knock on the door' is less clear to me.