In the building instructions for the water tower, a rubber band is required at one point. However, the caption in the task states: “is used without an elastic band”.
The caption is a rule change that the WRO Association decided on just a few days before the tasks were published. However, the pictures and the assembly instructions have not been adapted to this. If you have installed the rubber band, you may remove it, it will not be used in the competitions in Switzerland or the international competitions.