A major but often overlooked advantage of a trailer board is that if you are asked to remove it, you can throw it on the road, jump up and down on it and tell it in no uncertain terms what a so****ing useless waste of money time and effort it is!
This hurts no one and provided you pick up all the pieces, should result in you being waved on your way by a merry smiling policeman, something you may not experience very often, if ever!