I read this on another forum and it made me laugh out loud. However it'll need a few words of explanation for the Americans: in Britain film and television extras traditionally say "rhubarb rhubarb" to simulate the sound of background chatter. (Apparently the American equivalent is "walla walla".)
quote:
There was a bit of inter-services gossip in the late 1950s about a film in which a scene called for a warship to be arriving in port with the ship's company all standing on deck and talking excitedly. The Royal Navy agreed to take part and a suitable warship was found. The crew were all assembled on deck and told to keep saying "rhubarb rhubarb" to each other.
When the director called 'action' the warship steamed in and the film captured the Royal Navy chanting "Rhu-barb! Rhu-barb!" in unison, loud enough to be picked up by the sound recording and rendering the take useless.
(This is pure gossip which appeared in 'RAF Flying Review' at the time but I would desperately like it to be true.)
I don't think actors actually say "walla walla" or "rhubarb rhubarb" any more, as it tended to lead to fits of the giggles! Here's Wikipedia's take on the subject.