> I never assume that driving is a right, instead of a privilege, and the best way to maintain privacy is to just not participate in public activities in the first place..

You can extend that reasoning to public sidewalks. I mean, walking is indeed a "public activity" that takes place in a public space, so I assume that following your line of logic you'd be ok with any public authority following you or me (or anyone else for that matter) without any warrant, wouldn't you?