Of course, it will never happen. But suppose instead of striking, the police, prison officers, BAA staff etc just resigned, all leaving on the same day? I can't see the employers not negotiating in those circumstances, and as far as I know, a no strikes agreement or no strikes legislation doesn't cover a resignation. And we know from the police pay problems that the government does not negotiate (and apparently has no intention of negotaiting) in good faith.
Of course, without the Labour government's rape of pension funds since coming to power, BAA probably wouldn't need to consider closing the pension fund to new members. Another complication may well be that 'closing to new members' is a forerunner to 'closing and moving to a money purchase scheme'
It certainly was in my employers pension scheme!