that is not an assumption, as you say, fundamental or otherwise. It is a risk that they take that they can match staffing to the actual need as people arrive when they can only model how many will show up.
I think we would agree that the root of the problem is that there was likely insufficient staffing (I hinted as much earlier), and worse, no way to rapidly adjust staffing if the arrival prediction turned out to be wrong.
But there is nothing wrong if everyone shows up at once unexpectedly. that is a risk they take.
Heck, something similar to that happened once when I was working a ta burger joint in high school. We had 3 sations in the kitchen someone had fries and hot dogs, I had the grill for burgers and steaks, and someone else handled puttin ght orders together to get them out the window to the wait staff.
The orders came in the same window, and they were generally a mix of stuff from this station or that. We couldn’t see out to the dining area. Typical orders were anywhere from 1-5 meals.
So one day, an unusually large order came in, on the order of 100 meals in a 40 seat place. Hmmm, that was maybe 15 times what a normal very large order would be. As I looked at it to see what I needed to do, it seemed every one of them was for my station, and not a whit of work was required by anyone else. And all of the orders for me were different from each other. How strange!
Turns out my father, as a prank, got everyone he could get to come to the place unbeknownst to me (and to the great amusement of everyone else working) and order superficially from my part of the menu in difficult combinations. I wasn’t let in on the joke until I finished cooking everything. Which took a while, to be sure, not on the order of 5 minutes but maybe closer than 30-40 minutes of frantic unplanned work during which no new arrivals could expect the usual level of service for grill items.
So the point is, short term spikes in demand can wreak havoc with staffing, regardless of intentions. But if you open the gates, you have to deal with it. The way to solve that is to monitor at the gate before people are in, and maybe to slightly dampen demand, or at least peaks by noting via policy on the web and elsewhere, including at the gate, that management intends to not allow more people in than they are presently staffed for.
No way you can blame the failure to manage staffing well, or to manage the crowd so it matches staffing levels on the kids. They just represent a peak in demand. It is management’s job to handle those gracefully when they occur, and they have or at least had graceful options available to them. this happens routinely at clubs, restaurants, stores, pretty much anyplace where crowds come and go. It is not rocket science.
