Almost everyone who is concerned about severe food allergies has seen the recent study which shows that a huge percentage of food allergic kids gets bullied for having food allergies.
We've seen situations where adults have gone to restaurants and made specific requests that food items they are allergic to not be included in a dish that they've ordered. However, those food items were still in the dish and were actually concealed.
I could never figure out why that happened until I saw that study about bullying. I guess these are just the same bullies acting in the same way now that they are grown up and have jobs. I also can only assume that if they had been properly educated that doing this could seriously injure or kill a person, they wouldn't do it. So I put that as much on the employer as on the person who prepared the meal.