I would think patrolling a neighborhood would be a better use of time than patrolling a parking lot running plates
Odds are that the neighborhoods are patrolled too. Be it an 8 or a 12 hour shift, there's plenty of time to do it all... at least for smaller jurisdictions. I could patrol every neighborhood in my district, once ever 2 hours, pull over cars, do a DP, AND check plates in a parking lot... if I was a parking lot hound. Remember businesses are entitled to police patrols too. I've actually been flagged down by people before because I patrolled their area too much. They though something was wrong, and asked if they had to worry.