Google tracks your and eveyone elses interests all the time via googlesyndicate.com and facebook via the like buttons that are everywhere, and they may be forced by law to share that information with the goverment.

But goverments dont need google lattitude to get your current position, it is very easy to calculate your exact position if you know the transmitterstrength of your cellphone from several celltowers.
Also, when communicating over wifi, then the ipadress of that connectionpoint is easy to get from the provider, for some goverments.

This is actually a very good question, especially the question about the GSM radio
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Richard Stallman (the father of GNU) believes that society by accepting overt full time tracking implicates the innocent who don't carry a phone as a full time tracking device as suspicious.

It works like this:
For some reason, maybe you were cheating on your wife and visiting a girlfriend or just playing D&D with your nerd buddies near what unknown to you turns out to be a meth lab. After the cops bust the lab they do an audit of cell tower records a few months back and find you visiting at strange hours in the same vicinity, you are now suspected of being a top level drug dealer who is lying low after the lab bust. The cops finally get tired of you not selling drugs after following you for a few weeks probably with a good search warrant to tap phones and sneak&peek your house. They break the door with a SWAT team, shoot your dog, pepper spray your wife, cuff your kids, and haul you in. The cops offer to drag you through court and maybe even lie to get a conviction unless you turn in more drug dealers, they also can confiscate your home, vehicle and posessions with only suspicion that it was used in smuggling or selling drugs.

Kinda makes you wish you had not carried you standard issue human tracker with you everywhere not knowing if there was something suspicious that you might get tangled up in.

More likely is situations like the Arab spring(summer,fall, winter, spring, summere...) where governments may direct secret police to monitor the mobile phone network logs to track people.

Bing tinfoil hat about privacyis like being tinfoil hat about the law, you never know when you will be mistaken as a much bigger fish than you actually are. I used to be a SWAT team medic, the busts we made were sometimes ridiculous, the way the family of the suspect were often treated was even worse, so yea, I got issued a tin plated kevlar helmet.

so... does a N900 ping phone towers on bootup with or without the SIM installed?

Compare the power usage profile output from "powertop" before and after turning the GSM radio off. It's quite a significant drop.

Tracking device present or not, I think that getting strung up in one hell of a bust, where there are no ties to the act other than location and time, are more of a problem with your Friendly Neighborhood Police State and their Totally Legitimate Processes to achieve their goal.

They could do the same asking neighbors for people they saw entering and leaving, or checking traffic cameras for car plates, both of which can be avoided by not being seen, just like turning off your phone (and thus not being registered and thus seen by cell towers)

Oh, right, the real question.
IIRC, you can dial emergency numbers without a SIM.
However, until you do so, the N900 remains unregistered on a cellular tower. It's how my N900 lasts a week (no SIM) instead of 4 days (with a SIM, 2G, no data) with light use

Thanks, I got kindy of ranty there for a bit.
Does GSM have a special protocol for the no-SIM emergency number dials that cold fires up the GSM radio, associates with one or more cell sites, and then makes a connection allowing it to avoid pinging?
BTW this is on toipc today.
http://yro.slashdot.org/story/12/12/...hout-a-warrant

It's nothing special. The SIM is only used for authentication, but when you call the emergency number (112, 911, whatever) nothing in GSM requires the terminal to be authenticated.

In Germany, this is history.

You need to have an authenticated SIM now to make emergency calls.

The stated reason was that there were "too many" abusive calls

It actually depends on the carrier. Some networks may allow SIM-less emergency calls, some don't.

However, emergency calls should (and must) work with any GSM SIM, even if there is no balance.

This makes me wonder if running OpenBTS on a USRP with significantly high power output (and disruption/lack of other networks) could force phones to register on my network, and sniff the traffic.

Well, in theory it could be done at least with release 99 networking. The authentication algorithms are breakable in real time with current HW, so you could signal registration to your private network for a given IMSI and fake a connection to network. However, using that in a MITM attack is not so simple as you would then have to signal as UE to the destination network also.

http://en.wikipedia.org/wiki/IMSI-catcher

From that article:
Would be nice if our N900s would notify us (notification message) if the network is asking for something anomalous, such as no encryption.

I guess such configurations don't go all the way up to dbus, and I'm not (currently) sure from where such information could be extracted (libisi1, ssc-daemon, ???).