Surely this is a no-brainer? It is a strongly recommend, so not mandatory. But if you could afford to do it, and wanted to, why wouldn't you. In a way its just stating the bleeding obvious, you are safer with a upper body restraint, so hey folks, you should consider it. Seems a totally reasonable thing for them to put out. Or is anyone really going to try and argue it makes you unsafer so they are trying to force a stupid requirement on you.