Thanks for all the responses. I was quite amused by what everyone had to say! I have to say that I like the strategy of saying that the last guy took all my money - to try to avoid paying those "charges". In my case, I am not sure if asking for a receipt would have made any difference. That security screener who asked for the $100 from me did not even bother to lie about that charge. In fact, she made it quite clear that she was doing something shady. At first, she kept on whispering to me "give me money". I pretended that I could not understand her, but that strategy did not work. When I gave her $20, she asked for $100. I then put $60 in the outermost part of my carry on luggage. She then proceeded to do a very cursory search of my luggage and took the $60 and slipped in under her belt. Kind of lame, in my opinion. If this was all caught on tape, there would have been no questions what she was trying to do. Oh well. I hope she used the $ to buy some good food for her kids.