Originally Posted by sinoflyer

In queuing theory, there are situations were the "arrival rate" can only be described as predictably unpredictable. A bank, the UC, and any other airline lounge belong to that category. And I don't think I'm the only one who's ever experienced being the fourth person arriving simultaneously to a line with three idle agents -- it's not pleasant knowing that I had just become the outlier of the average wait time. So, even though I won't hesitate to ask, I can understand if the agent declines to work on anything but same-day PNR. They've seen plenty facial expressions of the persons waiting behind us.