If any of the Rex guys that go to ozjet do return of course they will lose seniority as they will be rejoining the company as new hires and they know this. It is a leap of faith to leave any job to join a startup company to one that is that is by comparison secure. They will also be subject to the new eba as far as i know Rex do not hire on a part time basis (although the duties on some occassions look like they are)