Instead of getting in to a peeing match of the law, even though I know what the law is because I checked in to it myself when I moved here 3 years ago I will only tell you my experience.
I have traveled with my boat many times at least 15 times a year with no plate on my boat trailer and these states include, MI, OH, TN, GA, FL, AL, AR and TX and not one time did I get a ticket for not having a license plate on my boat trailer.
Next up, during the summer absolutely ever two weeks I am in a different state for racing and I pull a 32’ enclosed trailer with no license plate. I drive through numerous states all over the US every trip and put on about 35,000 miles a year for racing and not once have I got a ticket for no license plate.

Not stating laws here just experience!!!!!!!!