I'm trying to think through this from a legal perspective. If I'm going from store-to-store around town, my understanding is that police are allowed to watch me and even go into the businesses and ask questions or pull security footage without a warrant. The information they gather is circumstantial and probably would not hold up in court, but they can use it as grounds to get a warrant. Let's imagine a different cas…
Some Google servers can do stuff that Stasi could not even dream about. The upper limit of Stasi was that all DDR citizens were to be Stasi employees or informants. Google can do it no-hands.
E.g. I am all for the Police ticketing speeders, but I don't want some automated spy network tracking me instead. At least the Police should have to work for getting me if I speed ...