The operative word being officially. I'm sure plenty sneak cameras through the processes without asking for permission. And quite a few people I know have arrived, been scrutineered, and in the hour or two gap before their practice or race they decide to fit that camera system they've been waiting for some spare time to fit. So it never gets scrutineered and they don't have permission.
And I've not heard of people getting removed from the sessions because of it. Not that I condone trying, and it's not my fault if you do get caught [/disclaimer]
