47CFR97.113(4) still prohibits encrypted communications on the amateur radio bands in the US:
"(4) Music using a phone emission except as specifically provided elsewhere in this section; communications intended to facilitate a criminal act; messages encoded for the purpose of obscuring their meaning, except as otherwise provided herein; obscene or indecent words or language; or false or deceptive messages, signals or identification."
Thus, anyone using encrypted communications would quickly find their connection dropped (if they were using someone else's node), or would be quickly triangulated and reported. Amateur radio operators are VERY protective of their bands and privileges.
Now, it might be possible to use some of these techniques on some of the ISM bands (47CFR18):
or, maybe even using the limitations in Part 15 (47CRF15):
And, of course, they could definitely be used up in the "uncontrolled" RF spectrum space (which is most of the way up to infrared now).
However, some of the things they'll be fighting are, with conventional radio equipment, they'll either be seriously limited to their data rate (2400 bits per second for unmodified VHF/UHF radio equipment, closer to 300 bits per second for unmodified HF radio equipment). Or, they'll be seriously limited in their range (for VHF/UHF/microwave/infrared bands). There's a bit of trade-off involving data rate and distance/power; for example, some of the QRSS techniques allow for minimal power for extreme distances, but at the expense of data rate (1 bit per second or less?).
Still, I think they're thinking that radio equipment can't be easily located, which is obviously false. Foxhunts (e.g., searches for hidden radio transmitters) typically take less than 30 minutes for a well trained team (and, there are a LOT of well trained teams out there). Even mobile transmitters can be pretty quickly located. I've seen some amateur automated bearing location equipment which will provide the bearing to a signal in well under one second (which allows for a dynamic, real time bearing, even for a moving transmitter).
Plus, there's a technique of performing "RF fingerprinting" of a transmitter's output that allows it to be uniquely identified (e.g., signal rise time, quiesce time, noise characteristics, etc.). Heck, for that matter, there has even been quite a few successes locating receivers, via their local oscillator radiation (e.g., British TV locator vans, radar-detector-detectors, etc.).
Thus, before Anonymous puts too much credence in this approach, I think they need to do a bit more research of just how many holes there are in it. Yeah, tracking down such an RF link may require that some people get out of their easy chair to locate them, but it's certainly possible (and, when you make those bureaucrats get out of their easy chairs, well, they're not going to be happy!). ;-)
Oh, yeah, ditto the comments about the US$10,000 fines, per day, for unlicensed radio signals. I saw a news article just yesterday where the FCC imposed a US$46,000 fine for a violation. You REALLY don't want to get them mad at you!