BAcabincrew,
That's not true. Just because your service agreements specify a number of crew per aircraft, it's legal, for example, for a full 777 to depart with 8 crew only. That's the legal minimum and doesn't mean there's no passengers on board. BA are working to scheme right now - industrial limits and agreements are suspended to all intents and purposes.
That, however, is the kind of thing BASSA would love you to believe.
MrB