I hate it when I'm waiting for plane and want to buy something small in eg Boots and they demand your boarding pass. Means rummaging through hand luggage, always worried I'm going to drop passport etc with queue building up behind. I read somewhere that it is actually a tax scam by the air-side shops and there is no requirement to show your boarding pass. Does anyone know if that's true and if so, any suggestions on wording to convincingly say no? Have just grumpliy backed down over a lip balm I know it's trivial and 1st world problem but have been travelling for more than 12 hrs and feeling a bit intolerant.