The tape and line has to be there for any line that may form in the future. If they take it down and then the line starts blocking fire exits etc, now they have to worry about re-positioning people and establishing boundaries so that people don't jump the line.
Additionally, by building in that maze they also helped to stagger the people who got to the door. For example, if there is a line of 10 people at the front of the maze and then 10 more people enter the "maze" and take about a minute to get to the front, now the line is no longer there. It gives registration time they need to process any residual line.
Seriously, if all people have to complain about was having to walk through an EMPTY line maze, I'd say Registration honestly has nothing to change.
The real reason why we left it up instead of having a way to cut through the lines was so that the people are staggered. We ended up making a cut eventually, once we were convinced that we wouldn't have a huge rush on Saturday morning, Sunday morning, etc.