Yep, I guess I walked into that one
I've done my time as a rampie, and on almost every flight, I would unload some freight/baggage and for one reason or another put it on the tarmac so it can be placed on top of everything when the aircraft had finished being unloaded. On more then one occasion, I must admit to having forgot about it and left it there. It is amazing how an honest human mistake can shut down an International airport for 12 hours.