Many years ago there was some summer camp and the staff organized a game "take a picture of your team leader without having them realize you're taking a picture". I completely obliterated the game by downloading an app that allowed me to record "in the background". I got a few good shots by showing a funny picture to people while having the front-facing camera on. Then I got other shots by turning on the back camera, locking the phone, and then just casually holding it in my hand like any other locked phone and waving it around.

The point is, if you want to secretly record, it's already trivial to do it.

So, your point is: "things are already bad now, no harm in making it worse"?