Because nobody wants to be caught holding the bag. I went to the ER once because of a bad reaction to a burrito. (Serious pain and my fiancé made me go)

When I needed back surgery a few years later, I attracted the attention of my insurer’s subrogation team, who tried on several occasions to get me to state that I was in a car accident during the burrito incident.

You get hurt in a big way, your insurer will make you sue.