I was going to say what GaryM said, and I think it stands.
Even though these aren’t heavy-duty trucks, the owner can still register them for 18k lbs. and therefore only be required to display a front plate.
A friend of mine many years ago recounted about going to a model train convention.(OK, that’s him) Somebody in the area thought it was neat to see so many outside plaes from all oevr North America, and decided to start a collection and dozens of people found their plates missing. (Not one of the brightest bulbs, but at least he had a hobby, I guess). The guy says the railroaders had a standing bet over who would be stopped the most number of times for missing plate(s).
I see cars with no plates from time to time. I thought people had to display the paper “temporary registration” but it does not seem many do. Of course, the real offense is not having registration, and there is some grace period. maybe these motorists in the OP are taking advantage off the police being tired of stopping people only to find they have legit reasons.
I don’t think farm vehicles in missouri need license plates
Googled “licensing farm vehicle in missouri”
The results are a little confusing and require too much thought for me now
http://www.modot.org/mcs/documents/FarmTruckSafety07.pdf
But Farmers don’t put license plates on tractors when they drive on the road. This exemption gets extended from tractors to ‘farm equipment’. Grain trucks would easily qualify by extension.
Interesting story. But you’d have to question the lead:
Check out the yacht - ostentatious by any standard.