In my experience the issue is no longer with cabin crews serving passengers too much alcohol, or even airport bars serving people too much, but with people actually pouring their duty free alcohol into soft drinks bottles so their innocent looking Coca Cola was actually an extremely strong vodka and Coke. When you are at the stage where the airport cleaners or handling agents are having to follow passengers into toilets because they have (often justified) suspicions they are decanting alcohol from its original container then you have to wonder about the direction society is moving!