Stupid newby question." weigh stations"... Does LE check records of those passing through the day before and of that day coming in and out?
I believe they do as I think the weighing of the truck is associated with a tax for that particular truck.
That aside, and with all due respect, I dont think the trucker possibility is very high. First, the truck would have needed to be left somewhere and unattended trucks in areas not assosciated with rest stops etc. stand out.
Though the truck could have been involved in a delivery to the meat packing plant, I have worked at two industrial plants in the past. Nearly all truckers are paid by the delivery and want to be unloaded as soon as possible to get back on the road. At one plant, some truckers were even rumored to "tip" our fork lift operators to unload them ASAP, even if the plant was not truly ready for the material.
For a trucker waiting in an unloading line to leave his truck prior to the unloading would be seen as very unusual and a grounds for a complaint to his company if he was not ready to move the truck up the line when needed.
A trucker leaving his truck parked to the side at the plant after being unloaded and not getting on the road again immediately would have been noticable and seen as odd. The truck would not only be taking up space at the plant, but the driver's actions would not be following their customary "get back on the road asap" principal.