Jumping Jack, unfortunately I've seen this happen. Three pilots due for posting from the squadron, with CFS a distinct possibility. One wasn't good enough, so was posted to Dominies. Of the other two, one suddenly announced that his wife was expecting and said that the disturbance of a CFS course and an unknown subsequent posting would cause huge problems.... So the singly was joe'd - but we all knew that the other pilot had planned things quite deliberately.... It does happen.
Still, a different RAF now - my best wishes and good luck to all those remaining after the forthcoming announcements.