Interesting... would love to have been onsite to try tasting some of those pizzas.
You still get a pretty good rise on the crust, and I've always questioned the whole "pushing air out" explanation about using a rolling pin. Besides your rolling experiment, here's why I question it:
Start with a dough with decent hydration, open it up by hand, and toss it into the oven with no toppings. You'll see rise from the center, as well as a bit on the exterior, right? (a rimmed puff, and larger center puff).
Go ahead and take a decent hydration dough and roll it out. Throw it in the oven. It puffs up, right? There's still air in the dough itself that allows it to puff and rise.
So given the rolled dough, if you have toppings in the center, the air still has to go somewhere. With the weight on the center, the air would likely move towards the rims, as it has the least resistance, thus still providing some level of rise.
I'd have to do some testing, but I'd be curious just how much more rise you can get when opening by hand vs. using a roller softly. My theory is that with opening by hand, you'll capture more air and likely provide a more airy corncione, but I don't know if a roller would really reduce it that much...?
Anyone do multiple side by side tests at all around this in the past?