The whole thing smacks of an utter non story drawn up by people grumpy at being reminded that they've signed a contractual agreement which includes reserve service.
As far as I can make out, the regular component of the reserve has been used in tiny, tiny numbers since 2003 - I think it was used to find a couple of deep specialists who werent in the TA or Volunteer reserves, and even then I got the impression that it was done on a 'would you like to come along, if so then let us know and we'll call you up'.
The regular reserve is a bit of a historical legacy - great if you're planning for WW3 and Russians over the border, but in reality, its not been updated as a contigency planning tool for decades. What it is now is a pool of people, some of whom choose to stay in contact with the RAF, and of them, a smaller group of people may chose, if asked, to enter service.
The reality is that there is not going to be a mass call up of ex regular RAF personnel recently made redundant, except in the febrile mind of a particularly poor newspaper correspondent. To get to the stage where the RAF is actively considering a general call up ex Regs, it would need to have exhausted the entire pool of regular manpower, put the volunteer reserves into 100% mobilisation and still be running short of people. I suspect if we're in that sort of national emergency, many people would be volunteering to come back anyway.
No sane desk officer is going to be putting a ministerial submission in requesting permission to compulsorily call up ex regular personnel who've just left HM Forces. Its simply not going to happen.
What has happened is that people have been reminded of their obligations, that they signed up to when they joined the Air Force, and they are now sulking because theoretically they may be liable at some point when its going very, very badly wrong, to receive a phone call saying 'would you mind'?
Its a non story except to people who like being easily outraged.