I went to change US dollars in money exchange few years ago and they asked that am I going to US or somewhere else. I didn't think about the question too much, but now my friend said that they have asked him the same question.
Why they want to know that?
First thing that came to our mind was that the quality of notes/bills they give is different regarding that are you going to US or not. Eg. they give worse quality of bills if you are going to US that them are taken out of circulation or changed to newer ones in US banks. Does anyone have any factual information about this? It would be interesting to know.