I'm not willingly giving up any information by being in a public space, because I don't have any choice about being in public spaces. Any information people gain about me is being taken, not given freely.

> I don't think going online is an optional activity either.

I think that can be debated, but let's say you're right: that just reinforces my point.

My essential point is that the "public space" argument isn't terribly meaningful. Actual consent can only be given in the absence of coercion. If being surveilled is a requirement in order to simply function as a human being, then consent doesn't enter into it.

And, in my view, all of the arguments about privacy and spying hinge on the issue of consent. If data is being gathered about me without my consent, then I'm being spied on.