And everyone knows, or should know, that you don't EVER put Swiss cheese on a Philly Steak!
Dude, half the time it's made with Cheese Whizz IN PHILLY!
So you can't get all cono-sewer about it. Although, truthfully, the other half of the time it's made with provolone sauce... which is... excellent.
Besides, this is a pizza, so everything is allowed (except some things).