Around here they are finally starting to crack down on pickups pulling trailers. They've done it to themselves by dodging the rules to blatantly. I see it all the time.
Here, any vehicle over 8,000 lbs GVW requires a state safety inspection annually unless you have a DOT number and actively run interstate (then FMCSA rules take over). I see dually pickups running here all the time with no inspection sticker.
Trailers over 5,000 lbs gross are supposed to be inspected too. NO ONE does that. Even I'm guilty there
. But, now I have a DOT number so I can do my own inspection per FMCSA. But I was formerly a rule breaker.
We also have intrastate operating authority. If you haul for hire within the state, you need it. I see guys with dump trucks get nailed for that. The fines are steep. But, many people ignore it.
Generally speaking, if you are a private citizen moving your own stuff around, you will not be hassled. When you start doing it for money or as part of a business, then you have to play by the rules.
It's a bit like prostitution. You can get your jollies off with anyone you like. But, if money changes hands, now the government has something to say about it.