I'm not sure what to think here. Legitimate misuse, sure. But the article says at least one person only looked up their own license plate. I feel like that should be considered acceptable. It's not law enforcement usage specifically, but can't I grant myself the right to see information on my own vehicle?
Yes, devil's advocate could say if standard citizens can't, no one can. Just seems so minor it's not worth losing a job over. All other cases (including plates of family which you don't directly own), yes, investigate fully and apply appropriate actions.