https://www.washingtonpost.com/national-security/2024/02/22/... has a fun story about a time at Fort Irwin (US Army laser tag in the desert) one side couldn't figure out how an attack helicopter got through their defenses, until they did some queries on a commercial cell phone tracking database and found the cellphone moving across the desert at 120mph. Hole identified, plugged for the next round.
And also talks about how the Ukrainians and Russians are having a great deal of trouble with cell phone OPSEC even after years of shooting war.