If there is a ban that is clearly not be taking notice of, do photo permits GCR style with a HV thats says it clearly so you can easily identify the legit people. Give them a breifing 1hr before the gala kicks off or something. Sell it for £20 or something, and make some money from it. Its something a few lines need to learn, I was at a railway and photographers were actually asking for this to be done! With the rude attitude before the event from some, and guilty unless proven innocent regime now, you're hardly going to win yourself any friends. If you can get money from being polite & forceful then so be it.