a bit, but the calls are simply meant to generate a high priority gsm packet (normal cell tower behavior) which will cause the handset to emit data in response to the cell network, allowing location fixing to move forward.

It doesn't have to be a no-ring call, it can be anybody at all with a legit call, text message, etc. Its favorable for the operator to do so in a way that will not alert the user, hence the no-ring call stuff.

In my experience some handsets will report fast hang-ups as a missed call, and others won't.

You can probably enable airplane mode/rfkill to shut down this threat from the less spooky nerds who would use it. No GSM radio = no GSM packets.