As Julian entered, he held up a hand in a nonthreatening position, and then retrieved the letter again, holding it out to them. There was no rule saying he had to come by here, except that there were two practical considerations. For one, this was beyond a doubt a two person job, so this was the best place to get help. Secondly, it was just good manners. Poaching from another Guild's turf was a surefire way to start problems. If you came, made the proper respects and promised them their due 3% cut of any take and then left after the job was done - or switched your status to being a member of the local guild - then things balanced out fairly well, at the end of the day.