The people that I see riding without lights tend to be people who got a $5 flea-market bike or one that they found in a basement. Many times, these people either aren't aware that proper lights exist, or feel intimidated to seek out where to buy lights. They've never been to a bike store, and many of them feel that a bike store isn't for them, it's just for people with the $2,000 bikes. Therefore, finding ways to give them opportunities to buy them outside of bike stores would be beneficial.
Instead of the police pulling people over and just writing them a ticket, why not give them the opportunity to get a blinky right there? Police often carry bicycle helmets in their trunks to hand out to kids, blinkies could be another great addition.