Pizza Girl, and her arch-nemesis Chinese Delivery Man, would be a recurring action-adventure cartoons or ads (or both?) on the TV that the QC-ites watch, much along the lines of Itchy & Scratchy.
Their occasional apearances in real life, delivering the fine comestibles they're known for, would have the same kind of responses from the studio audiences that you'd get whenever a guest visited Pee-Wee's Playhouse...