I was a rebel last night and put the pizza directly on the oven rack as ordered. Worked nicely. Usually I put a pizza pan on the rack when I start the oven, then put the pizza on the hot pan. That works well, too, and less chance of mess.
Oh, and @jaytkay, did you know that you can buy Teflon sheets for the oven floor? Instead of replacing, you just wipe anything that falls.