A number are now quite experienced fos with no prospect of a B737 Command in their base for some time. Others just would like a choice of somewhere to live other than the big 3, SYD, BNE or MEL. Some like the idea of progressing to widebody international ops.
Mate, Im sure there are plently of Guys in Mainline that would like those oppurtunities too, right before they were sold out by the JPC, who agreed to an absoloutly sh*thouse deal, particularly to secure the International flying.. So crap infact the deal that they dont even want to work to the agreement!!!
You are kidding if you think there would be a stampede!