Hellooooo differential enforcement. Cool, I can be legislator AND cop.
The point is to use "common sense".
When I was 16 and wanted to be a cop (not any more) I was a member of the Sherrifs Explorers. We got to ride along with the local deputies... On the very first ride along I did, the Sgt I was riding with came upon an elderly lady doing 25mph on the freeway, so he pulled her over (took a bit for her to realize the pretty lights meant to stop, as she put it).
Long story short, after explaining to the dispatcher that yes her D.O.B. was something\something of 1905, it was determined that her license was suspended and she had a warrant for failing to appear or something like that (I think, that was a few, err uhm, many, crap I am getting old, 20 years ago)
The Sgt, rather then cuffing her, considered the situation and we drover her to her house. Once at her house, we tracked down her son (scared the heck out of him, he was very concerned about his mother) and he was due to be out visiting her the next week or something like that. He agreed to work with her, get an attorney out there to help keep her issues in order, and solve this open issue.
Granted, he may very well have been just saying what the Sgt wanted to hear, however, is there any argument that society was better off by letting her sleep in her own bed (aside from her 25mph on the freeway, that was scary) and not take up space and resources in a jail?
My point is that I was taught (and believe) that the point of government is to protect us from each-other (not ourselves). In other words, to protect a normal regular person from a bad guy - such as somebody that commits armed robbery, murders people, drives at 80+ mph in a 25, conducts business in a way that impedes free trade... etc etc
Now that even has some flaws in it - if everbody was required to stay indoors and resources were all delivered to the house by government aproved transportation then the level of safety would increase... But that is just silly, we then loose the ability to enjoy life, so we have to seek a balance. In my view the Sgt I was riding with was using common sense to balance his job with the actuall needs of society in respect to this elderly lady. I believe he made the correct decision in that circumstance. He very well may have made the same choice with this older guy, or he may have ended up spraying him just like these guys did. We were not there and do not know the circumstances.
Still if the law regarding seatbelts was not in place, that warrant would not have existed.... Of course its possible that he would have had some other warrant, that is just an impossible argument.