I wonder how many people have sat in line for almost a day, gotten tickets, and then fallen asleep in the theater because they're just so exhausted? OR not slept, but been so exhausted that they can't even process what they're watching and don't have any memory of it?
I read that that happened when fans watched an all-day marathon of the Lord of the Rings trilogy, when Return of the King came out. They sat in a theater for over ten hours, first watching the extended edition of the first two films and then watching the premiere of RoTK. When they went back later to see RoTK again, they realized that they had been so tired the first time that they had no memory of actually seeing the movie.
That's what I would be afraid of, doing the cancellation line. Sitting in the cold for over a day, getting tickets, and then being so exhausted that I fall asleep or zone out and miss the actual performance. Maybe when I was 20 I could have done it...