Recording warning

[dmurfet]

There should be a convenient way for speakers to cause a warning to appear on the screen of those attached to an Orb, telling them that this talk is being recorded and the means by which it will be distributed (i.e. at metauni events, some recordings are Public and others Unlisted on YouTube). We're currently too lax about this, and it would be too easy for someone just arriving to be unpleasantly surprised.