They allow you to do prep work in advance. Some people bring a lot of prep, others make everything on the spot. I did all the black pins in advance, and made the 150 bigger pins live.
They have about 4 kilns ready for annealing and keeping parts hot while assembling. My pins (tried and tested) don't require annealing because they are so small. Which was a good thing because I was the only one doing 'soft glass' (COE 104) and it requires different temps than boro. And kiln space was scarce. The kilns run overnight, and in the morning there is often some breakage to be fixed. Working in front of an audience and such time constraints is hard.
Raven Copeland made a (with quite a bit of prep) 4 inch marble. And dropped it half way through. He managed to save it, though.