Actually, Virgin have had board first priority since the end of last year, if not longer. It works well, because they control the boarding process with the annoucements. The first announcement is not DJxx_ is now boarding, instead it is DJxx_ will be boarding in a few minutes. Now, I've heard this once from QF in SYD, where the announcement was "QFxx_ boarding soon, so you can all just sit down again". DJ then does a PE, Gold board first call. Basically, DJ customers have been trained. QF needs to do the same, they need to take control of the boarding process. As it stands it is a joke - without even considering the farce around priority boarding. I'd just love QF to actually get some control happening, because I'm sick to death of being trampled underfoot.
oops: bit of a rant at the end - not directed at anyone in particular)