Dragon man,
It's a long way before any retrenchment ocurrs in mainline.
One departments intent (read forward planning) takes some time to filter thru to that of another.
What some departments forward planning contingencies shall be would also result from what concessions are available from AIPA at the present time.
Best explained as "what concessions we get will, determine the way forward".
Or, if we (read they) don't get the concessions we seek, we may just have to activate the the J* / Mainline MOU.