Apple blogger Kirk McElhearn decided to see what would happen if he dropped an Airtag in an envelope and sent it on a 100-mile or so journey across England.

Turns out, it does pretty much what you’d expect, periodically updating its location whenever it was in range of an iPhone with FindMy enabled:

AirTags aren’t designed to track something in movement; this isn’t like a Tom Cruise movie, where spies track a car in a city, seeing exactly where it is in real time. They are meant to be used to find lost keys, luggage, or other objects. But my experiment shows that you can track these devices to a certain extent.

The reason for this is the sheer size of the network of iOS devices that can locate AirTags. Apple says that there are nearly one billion iOS devices around the world that participate in this network, and that ensures that you can locate AirTags in most situations.

I don’t know if any of the truck drivers carrying the mail didn’t have iPhones. Even if they didn’t, it’s possible that if someone in a car driving next to the truck has an iPhone, then it would be spotted. Since AirTags use Bluetooth 5, the range is around 100m, but that depends on such things as interference, walls, and other obstacles, and testing would need to be done to find how efficient they are in motion.

Unfortunately, it didn’t all go according to plan. Airtags are supposed to have a privacy feature built-in that alerts anyone with an iPhone in range that there is an Airtag far from home, in order to prevent them from being used as surreptitious tracking devices. Apparently, the notification never came, no jailbreaking required.

The network of iPhones effect has a bit of a Dark Knight kind of utility/creepiness. I like the idea of Airtags a lot and, once I’m leaving the house more than once a week and traveling again, can see myself using them. That the built-in privacy protection seemed to fail here doesn’t bode well when millions of these are out in the wild.