To clarify: I don't care about the emergent behaviors to the extent that I would somehow make license plates private, which is a completely impractical idea.
The identifying info attached to license plates can be kept safeguarded. Even so, license plates can be used to fingerprint a vehicle. Eyewitnesses can attach identities to license plates; e.g. you can easily know the license plates of acquantances such as neigbors and recognize them in a different context.
Some kind of technological solution of nonce license plates. They would have to use display technology, making them fragile, poorly visible, prone to various malfunctions.
I think lots of these issues are scale issues. Most people agree having some sort of weapon is fine up to a point.. that point may be a knife or a rifle but most folks probably think private citizens shouldn’t have tactical nuclear weapons.
Likewise, license plates are fine, full real-time surveillance of all movement in your country probably not great and not something the public wants.
Almost of these slippery slope issues are scaling problems, especially in privacy. Tracking people with cookies at your site, probably fine, using third party cookies to track everything your visit on the internet, maybe less great. Etc etc.
Legislating scale seems to be something that is particularly difficult since it’s easily argued, as you did, that’s it’s not inherently bad.
The identifying info attached to license plates can be kept safeguarded. Even so, license plates can be used to fingerprint a vehicle. Eyewitnesses can attach identities to license plates; e.g. you can easily know the license plates of acquantances such as neigbors and recognize them in a different context.
Some kind of technological solution of nonce license plates. They would have to use display technology, making them fragile, poorly visible, prone to various malfunctions.