Here are just a few things that happened to my friends and me while we were LARPing. My brother, who always played a thief, found a really good hiding spot on top of a tree. He waited in the shadows for groups of adventurers to pass below and then jumped behind the last person in the group, quietly backstabbing them and taking all their money. This worked like a charm until one night he miscalculated his jump and took a sword straight in the eye. Sure, it was just PVC tubing covered in foam, but it still caused substantial damage, and my brother had to be rushed to the hospital, nearly losing his eye.
Another friend took a wrong step and fell off a small cliff, breaking her leg, and another friend got arrested because a random police car went on patrol and came across a teenager wearing a dress running through an orchard while waving a big stick. When they stopped him and asked what the strange white powder he had in a pouch on his waist was, the idiot said, "It's just magic powder."