In the past BA have always tried to find things for the people they have chosen from ab-initio when things have gone pear-shaped. I would be very surprised if the FPP candidates were left without an option after training. As a member of IAG, BA would be in a good position to find places for them.
As said above however, this is quite a blatant stunt to put pressure on the government over APD. Pointing out that they are job providers, and that they will no longer be able to recruit without the government changing their minds over it.
Just a few days before we hear back, really hope it's not going to affect the numbers.