$5 Bluetooth tracker in postcard exposes $585M Dutch warship’s location for 24 hours

A Dutch journalist demonstrated a major operational-security flaw by slipping a $5 Bluetooth tracker into a postcard that, once aboard the $585 million HNLMS Evertsen, broadcast the frigate’s real-time location via a crowdsourced network for roughly 24 hours. The incident, enabled by lenient mail screening and a tracker “phone-leeching” design, prompted the Dutch Ministry of Defense to ban battery-powered electronic greeting cards and renewed scrutiny after similar location leaks, such as Strava activity on France’s Charles de Gaulle.