Ricon is right. Don't forget that, rather than PVR, you can write a letter stating your intention to leave at a particular point, e.g. end of timebar. They can't actually do anything until you submit formal PVR paperwork, but the point will be noted.
Does anyone know how to post a survey here, or link it to here, to see how many people are intending to leave at the end of a timebar rather than stay in? I don't know how to but it would be interesting to see and compare to known numbers of active pilots in the Corps i.e. not those flight safety liabilities in HQ DAAvn.
I for one will be voting with my feet!