As technological stuff gets cheaper, there will be way more surveillance, in the sense of recording everything with cameras, and I don't think that's necessarily a bad thing.
I currently support having police officers wear cameras to record all their interactions with civilians. It protects both the cops and the people they interact with from being falsely accused of assaulting each other.
There will come a time in the not-too-distant future when probably everybody will wear cameras (almost) all the time. It's a good way to establish an alibi so that you can't be falsely accused of robbing a bank or whatever, and also a good way to identify and catch wrongdoers such as purse-snatchers, pick-pockets, muggers, et al. You'd have to constantly stream/upload to the cloud so that a mugger can't just steal your camera to destroy the evidence.
What I would want to protect against is the government (or anybody else) having access to your uploads without a warrant -- a real warrant, not the kind the NSA gets. If you're accused of robbing a bank on a certain day and time, you don't have to produce your recording from the relevant period, but if you don't, the jury can make a negative inference against you. You should have the right to encrypt your uploads, though, without the government having a key.
I don't want to get too far off on a tangent ... I'm just saying that running license plates seems pretty trivial compared to the sort of privacy issues that are coming once everything that happens in public is recorded by everybody.