I recently visited the Schönbrunn Palace in Vienna. My ticket had an entry time printed on it. I arrived at the entrance a few minutes before that time. There

I recently visited the Schönbrunn Palace in Vienna. My ticket had an entry time printed on it. I arrived at the entrance a few minutes before that time. There was a long line. I asked a few people to see their tickets. All of them had entry times after mine. When my time was on the display, I asked the person in the front of the queue to see his ticket. He still had a few minutes to go. So I pointed at the time on my ticket and entered before him. He felt cheated, but as we together wondered through the museum, he agreed with my logic. My point is that online booking systems can make many lines obsolete. This article though touches on a more difficult problem, namely congestion.