I don't imagine there was ever any truth to that rumor. Airlines are competing for ever-evaporating talent. A quality company like Delta would be foolish to arbitrarily disregard an entire airline worth of high quality pilots such as those working at G4. As a bonus, Delta could probably save money on sim training as Allegiant pilots have already seen it all.

Expect many more to be getting calls from reputable carriers soon. My airline has changed its hiring standards, others are too. The pendulum has swung.