The alleged Russian covert agents uncovered in the suburbs used ridiculous communications methods: I'm flabbergasted by the techniques described in the FBI complaint about how the soi-disant spies communicated. In at least a couple of cases, the FBI states, a Russian official and one of the accused covert agents used ad hoc Wi-Fi to communicate over short ranges.
I suppose this seemed like a sensible method...to a six year old, although I wouldn't want to accuse a six year old of such simplemindedness. Perhaps spycraft for Russians hasn't caught up to, say, 1999, but needing close physical proximity is a simply bizarre requirement for passing information.
Ad hoc networking broadcasts information about the senders all over the place, which the FBI captured. The communicators clearly didn't even change the MAC address (the unique Wi-Fi adapter number) or the ad hoc BSSID.
I won't be surprised to learn that they were using WEP encryption, which the FBI broke, and lacked a layer of encryption on top of that.
Without jeopardizing national security, because I don't know anything that every attendee at DEFCON isn't better aware of than I am, I would have used one of the following methods.
Ultrawideband (UWB). While UWB hasn't caught on, there's plenty of gear out there. Indistinguishable from noise without special equipment, two relatively close devices could shift tons of information rapidly via UWB without creating overt attention.
Public Wi-Fi. Creating an ad hoc network is suspicious. Instead, the two parties communicating could log into a cafe network and use local network discovery to create an encrypted tunnel. That could be spotted, too, but it would appear potentially more innocuous.
Public Wi-Fi in freaking different locations. Explain to me again why, what with the Internet and plausibly unbreakable strong encryption, VPNs, and other obscuring tools, why spies would use close proximity to exchange data? Log in 100 miles away at separate cafes, create a tunnel between the two machines that doesn't betray origin, destination, or contents, and there would be vastly less to make a case on.
Now, I suggest these methods not to encourage spies, but because every goshdarned techie with any slight knowledge of encryption and wireless communication would think of them first.
The former Soviet spy agency is clearly not recruiting from its elite Internet hacker division for wet ops.