Just spent 2 hours lifting my 120ish shade 1 level on Ely hecks. Died 4 times. Mostly cuz the newbs in the team decided to do such things as...
1) run off to loot old corpses instead of sticking with team (when they were the lead tank)
2) pulling multiple mobs at the same time
3) running into kiting areas when it was obviously a fresh wipe (and the kite was boiling CF in view),
4) hang out in a respawn area when the hecks were a-popping.
This is stuff that most vets won't do. How can you tell who's a vet and who's not when you're picking from a field of alts and newbs? You can't.
Don't get me wrong. There are incompetent vets or overzealous ones and everyone makes mistakes sometimes. There's no gauranties.
But there are probabilities. And the probability I'm going to get stuck with someone who has no clue about their role or situational awareness will be lower if I team with vets.
So... I suggest a visible flag that peeps can choose to display or hide that indicates the time - in days, months or years or whatever - that their account has been played.