For a few years, I worked in the kitchen at a busy convention center in Boston. We had a couple cafeterias, some snack stands and a restaurant. During super busy shows, we added speed lines and some very portable stands as well. The decorating company laid out the booths and created aisles for the show with pipe and drape. Then the decorators used various methods of crowd control.
At the ticket booth, retractable belt stanchions were used to keep people queued up safely and to minimize the space for the queues themselves. Stanchions were also used at our cafeterias and snack stands to form queues to keep diners in a small area so they wouldn't block the vendors booths. Moving food and equipment around was difficult during these busy shows. We often tried to get in very early and move our stuff around before the show opened to the public.
At our restaurant, we used velvet rope to funnel guests into an area that wouldn't disrupt regular traffic flow. The entrance to the lounge was at the end of a short corridor with doors leading to meeting rooms and conference space. The velvet rope was placed along one side of the corridor and diners waited in the queue until the hostess was able to seat them.
In some instances, a show would include retail space as well as the convention itself. In these cases, barricades were used to keep the show area separate from the retail space. Very often, we had a speed line or a small gourmet stand within the retail space. The decorators always created a small opening in the barricade for us, so we could move back and forth between the kitchen and our stands without disrupting the traffic flow. These entrances were often hidden behind pipe and drape, so they were not visible from the show floor.
I liked my work at the convention center even though it was quite challenging at times. It was hard to move huge carts through masses of people who may not be paying attention to what was happening around them. I learned quickly to use an outdoor voice. "Behind you!" and "Hot stuff coming through!" worked well for the most part. But there were times when the show was so busy, and the queues overflowing, that we had to pause and wait for the crowd to thin and the effectiveness of an outdoor voice was lost.