Thankfully have not yet missed a flight but witnessed someone who did. Flight was LHR with a refuelling stop in Bangkok and on to Bali. Three British gents who were in the their late 40's got on board and sat not far from us. They had obviously had quite a few drinks in the bar before boarding and had brought a bottle onboard. At Bangkok allowed to get off the plane for 45 minutes to get a coffee etc. Two of the said gents also get off with one in bare feet !!!. Just before the doors close only one of them returns, minus the gent in bare feet. As they were close heard the conversation along the lines he couldn't find his mate anywhere in the terminal and his passport was onboard. God knows what the Thai authorities made of this Brit in bare feet with no airline ticket and no passport.