A similar incident occurred at VS several years ago!
A crew member got on the PA thinking they were making the PA to Crew Rest, when in fact it went to the whole cabin - "Wake up you C**ts, we need to feed the pigs".
A similar thing also happened at VA, the PA was slightly less crass - "Wakey Wakey Hands off Snakey"
Maybe a Virgin thing, but I am sure it has happened at other airlines.
Just a bunch of losers trying to be funny! Go get another job!