What Peter Somerville is alluding to is the fact that few if any of the pilots applying from outside Australia would have their standards/employment records easily verified.
If these Jetstar positions were filled by QF mainline pilots under the MOU, then Jetstar would know exactly what they were getting.
Qantas went through the DEC route many years ago and that was the problem they faced then. Some of the DEC's in fact never got a command because their standards were far below how they had represented themselves.