With regards to the incident in New York. Trying not to speculate too much, however with all our CRM training etc cabin crew must understand that if the flight crew says it's save to fly it is. It is not really a democracy, especially not with cabin crew. Sure they can voice their concerns and it is the flight crew's job to assure the cabin crew, but the cabin crew does not decide if the aircraft takes off or not.
If they do abandon ship there is not option of flying anymore, you can't go with less than the minimum crew compliment (unless you ferry the aircraft).
(Not working for Norwegian anymore)