If I want to record you, you'd never know.

https://www.dpreview.com/news/4272574802/omnivision-has-crea...

So all the people blathering about camera in public have a moot point. All the whining does is prevent the fairly obvious camera being put into devices.

But if someone wants to record you in public otherwise, they will and there's nothing you or any of us can do about it.

I think your point is a little black-and-white — there's tons of behaviour that sits in the "technical possible but frowned upon" bucket.

It's like people listening to music without any headphones on the train — technically has been possible for ages but previously would've gotten you told to turn it off. Now it barely gets a raised eyebrow.

Can you prevent people secretly filming you? No, but most people still don't want it be become accepted behaviour, even if to you that's all just "whining and blathering".

The thing is, every beginner lockpicker makes a similar point when they realize how easy most locks are: "what's the point of locking my door if anyone can easily get in anyway?".

I think the same answers apply here: because making it harder to be casually recorded sends a clear signal that you don't want it, and now the act of recording goes from being an oversight to a deliberate, sometimes punishable act.