Further to my earlier piece, I'd like to point out what the "opposite" of having cameras everywhere is:
It's having people follow you around to make sure you don't take photographs.
That sounds silly, but it's not hypothetical, it's real, now.
Where's the principle here? Am I more free if I can take a photograph in a public place, or if I can't. And if I can, why can't a shop-owner or a bus company or the police? And if I can't, how intrusive to privacy is it going to be to stop me?
I admit that just because it is legal for someone to do something, that doesn't make it good public policy for the Government to do it, too - that has to be argued separately.
But I do think the freedom to take photographs in public is more fundamental than any right not to be photographed in public.
Related: Kinds of Privacy