I think it is not unlawful to relocate your plate to the lumber stack so it can be seen, and at night the plate needs to be lit by one light.
In states that require a plate on a TC and consider the TC a vehicle in itself then of course you cannot put a truck plate on a TC, but in the rest of the states in order to display your plate then putting it on the TC or lower on the truck would be correct, but not to say leaving it on the truck and blocked is not incorrect…
Any judges here?
When towing a trailer behind a TC, then it is maybe fine for the truck plate to be blocked since the trailer plate is visible.
Does the truck plate need to be visible when towing a trailer with a visible plate? Very few truck plates are 100% visible when towing anything.
I once got a warning ticket for no violation, just stupidity on the ticket writers part, and he had to crawl under the TC to find the plate on the truck. No warning for improper display of the plate, and I bet he had no clue about plate display rules to begin with so did not think to write me up for that, if it even were a violation…
Generally, people towing large RVs or hauling TCs in their truck are not ones on the run or that require quick plate reading by authorities, so this is not high on the list. If you drive a sports car and have plate issues, then likely another story altogether…