Hehe. Quite true. Nice catch. But since MessageBox() takes two LPCTSTRs one would have to know how to pass in C style strings in order to get it to work for them. So in this instance I can see how some might question a person's knowledge of C/C++ if they did not know how to get MessageBox() to display what they wanted.
I think the question they meant to ask was "Spidey, how much Windows programming have you done?" (since I imagine there are C/C++ programmers who have gone their whole lives without using MessageBox).