Whilst individuals may not know whether they specifically are to be chopped, I don't think it's fair to say it was leaked before anyone knows: all the trainees had briefings last week to the best of my knowledge.
Heartbreaking as it is, continuing to train a large number of aircrew who have no seats to go to doesn't work out. Given that 5000 have to go, would you rather it were those already qualified, productive and who've had (potentially) even more invested in them?
I don't think anyone's contract is finalised until completion of phase 2 training, though what the implications are of moving the goal posts part way through the training cycle I haven't a clue.
None of this was ever going to be terribly pleasant.