The Cuckoo's Egg, Cliff Stoll

While it's a bit dated on the technology front, it's an incredible (and true) story of tracking and prosecuting an international espionage ring as told by a Berkeley post-grad astronomer who really had no business working in the Lawrence Berkely computer lab. It's fun, often humorous, and includes cautionary wisdom about using a microwave to dry ones' sneakers.

We're not at the point where people are shipped off to the nearest gulag in a boxcar for exercising a basic constitutional right. Why bother with the subterfuge when we have a much more efficient mechanism to silence people? The justice system is shockingly effective at destroying lives and careers-- just being accused is enough to disqualify you from many opportunities.

More than likely, the people you saw being carted off in restraints and disappearing from the grid are COINTELPRO-esque operators. Not saying that the FBI is involved, but it's pretty easy for local law enforcement and corporate entities to insert their own personnel into otherwise peaceful protests to attempt to turn the crowd into something worthy of a police response. We saw plenty of it as the Occupy movements wore on.

These external actors are the easiest to martyr to deliver the threat of adjudication to the rank and file protestor. Consider it really, really good theater.

-SS

As a previous poster suggested, about the only shoestring option that you have (and able to withstand legal scrutiny) is whitelisting. The downside is that it's a morale killer and you have to answer regularly to accusations of playing the morality police.

As you stand a chance of experiencing legal penalties, your leadership should belly up for a proper tool. My personal pick through my years of managing this function is Websense Web Security. It's not as expensive as you might think, especially for what it brings to the table. Their pricing fits nicely for nearly any size of organization. I currently manage a 5000 seat deployment, and I couldn't be happier with the job it does for me, or the minimal amount of care and feeding that the system requires.

-SS