Though things like this shouldn't happen, I take instucitions from A/G as an advisory, certainly not an order.. .. .I say advisary, as I would expect ( read hope ) that they know more about what is happening at that airfield than I do.. .. .As P1, your in charge ( & ultimately responsible ). If it's not the right thing to do, don't do it! Personally, I wouldn't sit on a runway & wait at an A/G airfield.. .. .BtB