I used to work in the restaurant industry and you would not believe how many people were “allergic” to onions. Far and away, it was the most common customer allergy we encountered. Ten times more people were “allergic” to onions than all of the top 8 allergens combined. You’d think onions themselves might be on that top 8 list with how many people claimed allergies to them.
(C’mon, just say you don’t like onions, don’t lie about having an allergy.)
I had a baffling refusal-to-modify-a-pizza experience at Pizzafari in Animal Kingdom several years ago. They sold veggie pizzas (regular cheese and vegetables) and they sold dairy-free plain cheese pizzas. I asked if I could get a veggie pizza but substitute dairy-free cheese. They said no. I said okay, can I have a dairy-free cheese pizza, add veggies? Again, they said no. Couldn’t do it. Impossible to put veggies and dairy-free cheese together on a pizza. And this is Disney no less, where they are usually very accommodating of modifications.
I can count on one hand the number of times I’ve asked to speak to a manager in my life and this was one of them. The situation seemed so absurd that I thought the employee must be wrong but nope, the manager backed them up and said they couldn’t put veggies on a dairy-free cheese pizza because of allergies and liability. “But I don’t have allergies. I never even implied that I have allergies. I’m ordering dairy-free cheese because I’m vegan.” Nope, wouldn’t do it.