It's hard to imagine an immediate grounding of all say 767s / -400s immediately as they are still happily selling seats on flights well into the future on those types.
Also, they're spending an absolute bomb of money reconfiguring 9 of the 747's.
But that sort of action would be well rewarded as decisive and excellent action in the business community with bonuses all round for a job well done. So I personally wouldn't be suprised.