hi lobey, think they tried this a few years ago with crew on FRA slips. didn't get much interest as you had to be available at short notice to get back to FRA if someone went sick. try this for a scenario, you book and pay for a weeks accomodation in southern france, buy confirmed ticket back to FRA at the end of the week. crewing calls you morning of day 3, you have to crew back that night to SIN. you lose confirmed ticket back, 4 nights accommodation and no compensation. now if they couldn't have dragged you back kicking and screaming before the week was up maybe it would have seen a much higher take up.
not having a go at you, tell telling you how it WAS.
p.s. a mate did take it and didn't receive a call from schedulers. maybe a slight error in his contact number helped.... Hmmm