Generally "I wasn't driving then" is actually a defense to the automated cameras. The registered owner things is just the first pass like any other lazy investigation.

In the broader context PII is a looser concept, and can be thought of like browser fingerprinting. The legal system hasn't formalized it nearly to the same degree, but does have the concept of how enough otherwise public information sufficiently correlated can break into the realm of privacy violations. I. The browser fingerprinting world that's thought of pretty explicitly in terms of contributions of bits of entropy, but the legal system has pushed back on massive public surveillance when it steps into the realm of stalking or a firm of investigation that should require a warrant.

PII isn’t limited to SSNs. By your logic, First name can’t be PII, and last name with no accompanying info wouldn’t be PII. Different types of data have different risk profiles. When multiple records about an individual are collected the risk grows exponentially. Location is absolutely PII when combined with other risky data, like license plate.