This reminds me of this rumour about how someone used tinder to triangulate opponent units during an exercise and arty them to shit. Supposedly Finns outwitting Norwegians, but is a anon text so who knows: https://imgur.com/gallery/bySUH
They might not wear them out on patrol or manoeuvres, but back at their tents/barracks, I would assume some if not all have their personal phones. You only need a couple to track them.
I also read once Strave/Fitbit type trackers was rife at army bases and used to work out patrol routes.