This is really annoying. Yesterday I was in a party for Caravan Escort and I didn't get in a run because some people outside the pt talked to the NPC a little before me, so it reached the members cap. Needed to leave, also because the party leader started kicking everyone who didnt talk to the NPC in time.
And let's not talk about the rude players who accuse you of "leeching". I was fighting as well, but the mobs went down so fast because the lv50 BLMs did most of the work with their area spells, I couldn't do much.