It's only creepy if it's done on a targeted, individual basis, which it won't be.
As it is - in many countries you legally have no expectation of privacy in a public place, so I have no problem with en-masse ANPR. If the police eventually develops a very dense sensor network that can track every car's movement across every intersection then there would be too much information recorded for me to personally worry about it - and I still believe it would help with crime in general. The usual reactionary bullet-points based around the usual bogey-men of terrorists and child-abduction are weak and I think distract from more meaningful and impactful, but sedate arguments: e.g. it would reduce the need for inherently-dangerous hot pursuits to follow a vehicle as the cameras would do that anyway. Uninsured vehicles could be identified immediately before they get stopped for a broken taillight or involved in a collision. And cynically: APR systems could be used to compute a car's average-speed between points to determine if the car broke the speed limit).
I don't feel mass ANPR is comparable to other bulk-surveillance schemes like Internet snooping, because I believe that we do have an expectation of privacy regarding what goes through our home connections, and acting on Internet surveillance is inherently subjective - whereas ANPR can indicate if a car is known to be stolen or uninsured, that's not something that's open to interpretation.
