Recording students does work. The knowledge that a teacher can scrub through and see what you are doing can scared the daylights out of me. Also they required me to show whole room so i couldnt have notes. Cheating would not be worth it!
It’s a false equivalency.
If anything, I suspect that on net a noisily invasive anti-cheating system would actually increase cheating, as more students would be tempted to see if they could game the cheating system than would be dissuaded from cheating from hearing about a cheat-proof system.
I can tell you with certainty that some cheaters are skittish. I am certain of that because I once wrote a bunch of trig identities on the side of my leg. I was very nervous about it, and only did it because I knew from previous tests in that course that I could get away with it. If the teacher had been walking around during that test, my pant leg would have stayed down.