...are self defeating. QF goes to great lengths to train guys on the regional networks, gives them lots of great experience in a demanding environment, then sends them off to crew competitor's fleets.
Experienced pilots are not the abundant commodity they once were, and providing a clear career progression path would ensure that the group retained most of its people. To do otherwise is a cynical exercise that is designed solely to benefit the "gentlemen" concerned.
Allowing regional guys an entry into mainline does not lengthen the training ladder: If a pilot goes to CX instead of inhouse promotion he still has to be replaced.
If I was a CP who treated people like chattel I would expect to get screwed by the guys often and thoroughly.