I am a bit suspicious on this one - not doubting what cabin crew may have been 'told', possibly to stir the crew up, but I can not for the life of me seeing such a vindcitive act being perpetrated - especially when this would present an opportunity to publically show the arhitect of such a policy to be literally anti-saftey in an environment where fatigue is close to the top of safety concerns.
As I said, if you can get proof, exploit it against the morons who have come up with this policy.