This is how I explained it to one of my friends who is/was definitely a member of “I’ve got nothing to hide” club -
Suppose you are in a pay-to-use toilet minding your own Business.
That pay-to-use toilet is managed by a public/private entity called ToiletBook.
Suddenly you notice a (hidden) camera in the room.
When confronted, the owner confirms the only reason they took your picture to suggest you the perfect underwear based on your size. And, there is a legal guarantee that picture/data will never be used for any other purpose and only be processed by machine.
Will you still go to such toilet?
BTW, that friend stopped talking to me afterward; not sure why 🤔 (Edit: I should stop giving shitty examples to anyone, as it seems ) 🤐