always astonishes me how often people go through security and then don't board... I was on an LHR - ATL Delta flight last year and the lady in front of me (business Class even!) was onboard and becoming increasingly agitated as hubby, who she'd last seen in duty free, hadn't showed.
Eventually the Capt came back and suggested she either travel or deplane.... he said they'd located her luggage as soon as she raised the issue just in case
She got off - I'd love to know the full story...................