I will quote my own post, tasteless as that is:
I'll try not to get bogged down by the nitty-gritty
I'm not trying to argue that people don't break the law; however, as a sweeping general statement, could agree that actions that are not unlawful are more likely to be performed by the majority of people than actions that are unlawful?
The reason I think it's important to at least try to maintain privacy with regards to license plates is that they are a matter of public record and, more to the point, we've instated rules that make it much easier to make that identification STICK. This contrasts with IP addresses, which are not a "public record" and the sharing of which is socially acceptable (or in many cases even encouraged)!