
Dubai bans the flying of national flags and banners from cars or buildings during the World Cup "for safety reasons".
(There seems to be an exception for UAE flags plastered across car windows, because as we know, Emirati drivers are safe anyway. Another reason could be that otherwise UAE would never have a chance to brandish their flag because they'll never make it to the World Cup. But that's of course just a malicious rumour.)
I think the recent Emirati approach is that everything should be banned unless specifically allowed.