Yes a community know their local sounds. The 4x4, bikes, luxury cars. They all have distinctive sounds and the local population are aware of any changes.
When an army of occupation or their local death squads move into an area that news travels fast.
Special forces try to blend in. Local death squads use what they are given. New machines with loud new distinctive sounds will stand out in open areas.
Counterinsurgency is now going to be robotic? An endless war of robot patrols and local robot checkpoint?
Divide a country up and pack the civilians into safe areas "refugee camps" to win hearts and minds?
Most people found outside a camp can then be tracked and questioned?
Back to a scorched earth policy with big numbers of new robots. Great news for the robot makers.

Re "I wonder who was targeted?"
When different network where still needed experts did find a few interesting past projects:
Greek wiretapping case 2004–05 https://en.wikipedia.org/wiki/...–05
The SISMI-Telecom scandal in Italy found in 2006 https://en.wikipedia.org/wiki/...

The code is of a quality set per user depending on OS, installed AV and all other understood networking conditions.
A consumer OS with standard trusted consumer AV and trustred normal OS updates?
A well understood open source install that a user looks over deeper OS level logs everyday?
The presence of unique new code a user "installed" and "allowed" is not going to report on huge anti-virus and anti-malware lists.
Will well understood behavior analysis on consumer grade AV be looking in the correct place?
Gov and mil know all about what AV can do and how unique code for one computer has to be installed so it is not really going to be found by consumer AV products.

Lots of nations can try. Italy had its SISMI-Telecom scandal https://en.wikipedia.org/wiki/...
Greece had the wiretapping case 2004–05 https://en.wikipedia.org/wiki/...–05
Now the world is seeing more software efforts beyond the expected gov tapping hardware and software.
So many staff around the world have done legitimate tapping for their govs and mil for generations.
Tame computer systems, networks have crypto that is well understood and of a weak international standard. Signals intelligence is great to sell to govs and mil. Ex staff, former staff and govs are all happy to see what they can get.

The only trick is getting local state and city officials to upgrade for 4G LTE without paperwork showing to local media or a FIOA request.
Cities scramble to upgrade “stingray” tracking as end of 2G network looms (Sept 2 2014)
http://arstechnica.com/tech-po...

Phone Firewall Identifies Rogue Cell Towers Trying to Intercept Your Calls (09.03.14)
http://www.wired.com/2014/09/c...
Will the next generation of rogue cell tower have the ability to be another normal cell tower?

Re 'Either the contents are not sensitive"
Think back to the early cell standards. Who set them and why? Emerging cell networks had to be safer from random strangers but totally open in real time to govs and mil needs.
Cost, time and who works on the telco networks can also be important to local law enforcement officials.
Why risk a computer database entry or tracked code change in a national or global telco system? A number or location is now been tracked.
Who at the telco has seen or can track the local or national law enforcement sensitive database changes?
Local law enforcement officials become the telco connection in an area for a time and the only people who have full details on who is been tracked.
No courts, no requests to telco staff or vast databases, no lawyers later, media, FOIA for paper work at a city or state level. Just all the call data.

Re Need to keep things secret?
Thats what the release of the records will show. Legal teams can go over past cases and talk about what was done to the press.
Issues of parallel construction, what legal teams saw or where not allowed to see and when can be talked about to the press.
Legal teams can then talk to the press about the use of a IMSI catcher, IMSI catcher like devices with denial-of-service attack options, location monitoring, transceiver amplifiers.
Meet the machines that steal your phone’s data (Sept 26 2013)
http://arstechnica.com/tech-po...
If the US wants a secret court it can talk to all the legal teams and find cleared legal staff and experts depending on the case.

Re "Thanks to the influence of such groups as the NSA your mobile phone transmits it's data in an easily readable format instead of something encrypted such as was first proposed for the devices"
Thats the idea. Fill the gps logs with random trips to locations that fit in well with the non fiction "story" on a networked computer.
Who was that journalists phone around or who did it stop near? How would it fit in with a story been worked on? So many new digital hops to follow up on thanks to one random drive and a long coffee. Keep adding to that non fiction "story" on the networked computer every few days. Start a new story.
Once people know they are been watched they can change. The old idea was never to talk about tracking. Now terms like cell-site simulator and IMSI catcher are in the local press.

Re continued, and expanded
With domestic surveillance now been talked about more in public the press now understands what keywords and interviews will result in.
The media can wait to type a report into a networked computer just before publication.
A journalist can also fill their networked computer with a lot of non fiction that reads like a real story thats been worked on.
Drive out with a phone on to meet a person with more information.
All the domestic surveillance teams have is networking. The connected computer, the phone, the operating system, the logs over years.
Once a journalist understands that part of domestic surveillance they can shape it.

Yes it goes back to the Trailblazer Project https://en.wikipedia.org/wiki/...
ThinThread https://en.wikipedia.org/wiki/...
Before that was Main Core https://en.wikipedia.org/wiki/...
Recall Project MINARET https://en.wikipedia.org/wiki/...
and going way back to the The Armed Forces Security Agency (AFSA) with Project SHAMROCK https://en.wikipedia.org/wiki/...

Re "So stop being paranoid. The FBI isn't going to after every donor to a project like this."
Recall "The NSA Is Targeting Users of Privacy Services, Leaked Code Shows" (07.03.14)
http://www.wired.com/2014/07/n...
"The rules indicate that the NSA tracks any IP address that connects to the Tor web site or any IP address that contacts a server that is used for an anonymous email service..."
"The NSA is also tracking anyone who visits the popular online Linux publication, ....., which the NSA refers to as an “extremist forum” in the source code."

http://pando.com/2014/07/16/to... (JULY 16, 2014)

It depends how the US military is counted. A huge number of civilian like staff, air force, army... could be used to hide deep counts.
So what can be counted on? The Air Force has very expensive equipment to look after. So great care is taken to only allow selected, well tested people near that equipment.
That would sort out most of the human issues long term and offer amazing statistics.
Other areas of the US mil may also like to have well tested people near some of the more interesting systems. Great numbers again due to expert testing and constant staff sorting.
The real issue is the head injury or meds used during long occupation tours.
Keep the best staff looked after and try and see what is left over for the rest.

Re "I'd put together a fake image which looks good enough to pass the sniff test for a day or two, but which is designed to "go off" shortly after when the public gets a chance to deconstruct it."
Some interesting ways to track this.
MI6 or CIA got something found in Russia and it was rushed out to the media. FSB just watched to track the origins, publication and expected Western media results.
Russia released the image internally to follow the image to expose some internal NGO or other well funded networks.
Limited hangout.
ie just to see something internal to Russia been activated.
Some other group set this in play and Russia, the US and UK are just interested to see where it tracks back and why.
So the value was not in the poor fake but its origins.