This trend is extremely dangerous. I could not agree more.

There's the massive intelligence collection and physical detection effort against terrorists.

There's been a more constrained system of criminal and criminal activity detection and correlation using GPS tracking, phone surveillance, drones, license plate recognition, and data mining of government and commercial databases.

The two are merging. Soon, everyone will be terrified of free speech and free association. Speech may still be free, but the government can always find some law you're violating.

As Breyer noted in his dissent in favor of granting cert in Rubin v. United States [1], "the complexity of modern federal criminal law... make it difficult for anyone to know in advance just when a particular set of statements might later appear... to be relevant to some such investigation." Even if you're guilty of no crimes and you have good lawyers, is participating in some political activity worth getting charged and brought to court?

[1] http://www.law.cornell.edu/supct/html/98-93.ZD.html