I've listed such mechanics multiple times already. Things like mob tags and non-sharable quest items imply "Get to it first no matter what, otherwise you'd do this quest forever. If others pull them out of your hands - you have to do the same just to equalize chances.". There is no way to get around this problem. Only "polite" way to do it - to respect your place in queue and not to try overtake other players. Problem is - game doesn't punish players for doing it. And therefore what isn't forbidden - is allowed. And other players have nothing else to do, but do the same.
I use traffic jam as example for reason. Guys, who're overtaking via roadside and oncoming lane are punished for reason. Otherwise others would sit in such jams forever.