We chatted for a while, and I felt really good about him. However, I had a gut feeling I should just check to make sure he could do the equivalent of fizz buzz. I said something like "Sorry for this formality, I know it might be seen as an insult to your experience... could we do a bit of coding?" His resume indicated nearly twice as many years of C++ experience than me.
I took out my laptop and produced three function signatures - one passing by reference, one passing by pointer, and one passing a pointer by reference. I asked him to explain the difference between the three. With a completely straight face and unshakable confidence he replied "no difference, they are all three ways of doing the same thing". I asked some clarifying questions, trying to probe the difference between pass-by-reference and pass-by-pointer. Again, he answered extremely confidently and coolly (but incorrectly).
"Err, no." I replied. "This ampersand here is a pass by reference, which means c++ handles the referencing and dereferencing of the pointer automatically. It's much safer than the other two, where you are ultimately dealing with a raw pointer and need to check for null pointers before dereferencing". Immediately he broke out into an uncontrollable sweat; it was really remarkable. Before asking the technical questions, I felt really good about him. I wonder how many companies he has fooled.