We had the same experience back in October. We were first sent through security in the main terminal, then after a very long journey to our LUF gate, were forced to line up again by the gate at an additional security checkpoint.

Problem was, they were ridiculously slow at the second checkpoint, to the point of causing nearly everyone in line to miss the flight to Chicago. Everyone else mentioned that they had been previously screened, so I wasn't quite sure why this was necessary.

Maybe it was a way of dealing with the "suspicious" post-Oktoberfest crowd