I could easily see it happening with a family group or a group of work colleagues traveling together. Everyone goes to get in the shuttle van or taxi, one person gives a couple of claim tickets to hotel staff, 7-8 bags are loaded by the staff on a cart and stacked in the luggage area of the vehicle and off you go! Of course I'd be looking for MY bag in the stack before leaving, but I wouldn't necessarily be paying attention to the other bags on the cart.