I think a similar approach was tried at Valley a year ago with students being told they all had to sign a piece of paper agreeing to stay in the Service if they were chopped from flying. They were told that they were already bound by their joining terms anyway but they had to sign to say they understood those terms; failure to sign would mean removal from flying training. Seeing as those terms were not presented to the students and they soon realised that the CO (of one particular Sqn) would be unable to remove them all, the students refused to sign. It all went quiet after that.
Personally I would challenge that order, request proof/documents etc and finally go and talk to a certain civilian lawyer who will give you free advice and is not too fond of the way the Services feel they can strong arm their personnel. If you need a name, PM me. You are the best asset the Service has, don't let them tell treat you otherwise.