Yet again, an app used by soldiers makes it possible to spy on them.

This was due to an unnoticed weakness in a "social" feature designed to increase user engagement by enabling a kind of interaction between users. But, at a deeper level, it was caused by using an app designed to snoop on its users, who are habituated to being snooped on and not in the habit of asking whether an app can do so.

Basically, if society is set up to track people in myriad ways, it will track secret agents, and abortion patients, in myriad ways.