Desecrates is the good term, reading the ketchup thing made me remember when I was in montreal at a fast food shawarma and pizza place, they also had poutine but with GRATED CHEESE, I was hurt
The dude who runs Shelby's makes funny tok tok shorts about ketchup on shawarma. He even has a set of recurring characters and includes customers in his sketches sometimes. This is an elaborate inside joke.
I don't get people who are bothered by others eating things how they want, but idk if my personal peeve puts me in the food purist category or a language prescrivist (I'm usually the opposite of it). I think food items should be called what they're and names should not be interchanged because the idea seems similar, like a crunchwrap isn't a calzone (the comparison I could recall from the top of my head)
Well here is where my PhD in tracking stuff on paper, which gets handed out in triplicate to every German child at birth, comes in handy. The signature line customarily includes the date again because printing date and signing date (and thus validity) might differ. And yes, I know this is not applicable in a restaurant (hopefully), but that's generally the reason when it occurs.