Pizza Hut's $10 Any Pizza, Any Size Deal

Pizza Hut has had a promotion for awhile where they say for $10 you can get any kind of pizza, any size, with any crust or toppings. I'm wondering why they  say "any size"? Shouldn't they just say "large"? Who's paying $10 to get a small pizza when it's the same exact price for a medium or large?

Is there a segment of the population out there that they don't want  to alienate by assuming everyone would want a large pizza? Are there people out there saying "Yeah can I get a stuffed crust pizza with lamb vaginas and  fried bananas with the ten dollar deal?" and the Pizza Hut person is like "You want large, medium, or small?" "It's ten dollars for any size?" "Yes." "Okay  well then I'll take the medium. I wouldn't want to pay the same amount for more food, that's ridiculous."