Although I am sure someone has already mentioned, I will add my 2 pence after being told by a GM to write here.

One of the most aggrivating issues was like this weekend for me, we were at about 5 people in the caravan, that built up to 9. But one of the most irritating things about it was there was 1 person sitting there crafting the entire time, only getting up to accept the quest again.

So not only did it take up a space so one person wouldn't get in, they didn't even contribute.