He was at an event. Frequently you're leaving stuff in the car between activities at various events. Usually this is fine, since you can lock your car, etc. Though since it was overnight, bringing it in might have been safer, but really, if you have a car packed with a crap-ton of heavy gear, it's not always practical to haul it in and out of a hotel every night while at the event.
This sort of thing makes me super mad, when it happens.
