Today, the threat is less obvious. It comes from those Apple Watches, Garmins, Fitbits, custom smartwatches and other remote sensors that track your location and share it with remote databases.

“These geolocation capabilities can expose personal information, locations, routines, and numbers of DoD personnel, and potentially create unintended security consequences and increased risk to the joint force and mission,” says Shanahan’s memo, which was released by the Pentagon press office too ensure everyone sees it.

This was all sparked when reports surfaced earlier this year of a fitness-tracking company, Strava, publishing maps showing where users jog, bike and exercise. Since many of its users are members of the military, their jogging routes and other exercises showed exactly where the US has service members around the world, as well as showing their running routes.

In Pentagon-speak, here’s the broad problem:

“The rapidly evolving market of devices, applications, and services with geolocation capabilities (e.g., fitness trackers, smartphones, tablets, smartwatches, and related software applications) presents significant risk to Department of Defense (DoD) personnel both on and off duty, and to our military operations globally.”

Strava apparently intended no harm but, you can guess how uneasy this made service members and senior Pentagon officials. A review of Pentagon policies about the devices that made this possible was ordered and that’s what this memo is all about.

Note the requirement for the Chief lnformation Officer (CIO) and the Undersecretary of Defense for Intelligence (USDI) to “jointly develop” guidance and training for commanders and others.