Having worked at a fast food burger place, there’s absolutely people that will order a “cheeseburger” and be surprised when there’s cheese. Not many, but it happened to me a couple times. We were also trained that “plain” means no onion and pickle, but leave the ketchup and mustard on as that’s how our PoS defined the term.

Sausage is ground meat inside a casing, traditionally animal intestine. When you eat a sausage, you become a sausage.