What purpose is served by ordering air marshals to wear suits all the time? To blend in? Nonsense.
There once was a man in charge of a state law enforcement agency in Oklahoma who ordered that all agents had to wear coat and tie all the time- including those working undercover. When the undercover people protested that this could get them killed, they were lectured about the necessity of their being dressed 'profesionally' at all times.
Happily, they got rid of that clown before anyone died/not in the best of ways, that's a different story/; hopefully this nonsense will be changed, too. Sounds like one more bureaucrat who's more interested in 'policy and procedure' than in getting the job done.
Kind of like the U.N.