Not too many FedEx "Home Delivery-Ground" trucks, UPS trucks, and DHL trucks that are the step-van/van type of trucks ever cross state lines. Most of those trucks are local and/or regional and never see the likes of a scalehouse on their routes. Maybe in areas like St Louis, Kansas City, or Texarkana might be areas where those trucks may pass a state line on their route, but I'm quite sure a Trooper aint going go chase one down for flying by the Coop without stopping since they know those types of delivery vehicles are not being used for Interstate Commerce.
As far as "Other Service Companies" that use those trucks, such as "Joes Plumbing" or Ralphs TV Repair". Again, not being used in Interstate Commerce, so Troopers probably let them slide. Now if a Step Van had "Pablos Nationwide Transport and Moving Service" plastered all over it, he best stop at that scale. Know what I mean.