When the Find My Device network came to my device I was literally asked if I want my device to be part of it, so even though by default it's an opt-out feature, everyone whose device can be connected to the network is asked if they want that to happen.
Seems like it's just another switch toflick off and forget about
Are you talking about American cops or these in particular, because these appear to be Ukrainian policemen
Edit: Nevermind, I found some sources. This photo was taken in Kyiv, Ukraine, during one of the protests of the Revolution of Dignity