I’m peripatetic.  My stuff lives in Austin; but, I’m in a different city every few days.  Lately looking for a new place for my stuff to await my return, I’m reminded of the first three rules of real estate investing: 1. Location; 2. Location and 3. Location.

Location has long been crucial in trial, too: “So, you claim you were at home alone on the night of November 25, 2014 when this heinous crime was committed!  Is that what you expect this jury to believe?”  If you can pinpoint people’s locations at particular times, you can solve crimes.  If you have precise geolocation data, you can calculate speed, turn up trysts, prove impairment, demonstrate collusion and even show who had the green light. Location and time are powerful tools to implicate and exonerate.

A judge called today to inquire about ways in which cell phones track and store geolocation data.  He wanted to know what information is recoverable from a seized phone.  I answered that, depending upon the model and its usage, a great deal of geolocation data may emerge, most of it not tied to making phone calls.  Tons of geolocation data persist both within and without phones.

Cell phones have always been trackable by virtue of their essential communication with cell tower sites.  Moreover, and by law, any phone sold in the U.S. must be capable of precise GPS-style geolocation in order to support 9-1-1 emergency response services. Your phone broadcasts its location all the time with a precision better than ten meters. Phones are also pinging for Internet service by polling nearby routers for open IP connections and identifying themselves and the routers.  You can forget about turning off all this profligate pinging and polling.  Anytime your phone is capable of communicating by voice, text or data, you are generating and collecting geolocation data.  Anytime. Every time.  And when you interrupt that capability, that also leaves a telling record.

Phones are just the tip of the iceberg.  The burgeoning Internet of Things (IoT) is a cornucopia of geolocation data.  My Nest thermostat knows if I’m home or away and senses my presence as I walk by.  The cameras in my home store my comings and goings in the Cloud for a week at a time.  When someone enters, I get a text.  We’re seeing cell-phone controlled door locks and motion-activated lighting “talking” via the Web.  Thanks to a free service called If This Then That (IFTTT), I can now direct Siri to turn lights on and off by texting them, at the cost of leaving an indelible record of even that innocuous act.  Plus, Siri is now listening all the time while my Phone charges, not just when I push the home button and summon her.  “Hey Siri, can you be my alibi?”

Many see this as an encroachment upon personal privacy; but, no one is doing this to me without my knowledge.  Geolocation technology is like a nosy next-door neighbor keeping an eye on things.  Wasn’t it Socrates who said, “the unexamined life is not worth living?”  Or was it Gladys Kravitz?

But seriously, I view this ceaseless stream of geolocation data to be a rich, untapped source of evidence.  I’m less prone to wring my hands about privacy when I ponder how this information will serve to bring down bad guys and protect the innocent.  It’s so much more than just a new way to sell stuff.

If you are one of those who worry, I’m about to ruin your day.  Still, I hope this tip will be something exciting to share with the family at Thanksgiving.  Log into your Gmail account and visit https://maps.google.com/locationhistory.  Set the location history to display 30 days, then start clicking around on the calendar.  Go back for months.  You may see nothing or, you may see (as I do), a startlingly detailed daily record of movements extending back more than a year.  You can even play it like a movie by clicking on the Play icon in the lower left corner of the map screen.

So, as to grandmother’s house you go, enjoy some breadcrumbs with your turkey and dressing.  Digital breadcrumbs.

Happy Thanksgiving, Dear Reader.  You, too, Siri.