1. Sponsors, especially at that level. 2. I believe they tuck them under the spandex bottom they wear under their skirts- on the outside of the thigh. 3. The net is tensioned at either end and in the middle. The middle part is anchored to the ground. The purpose is to keep the top “rim” of the net uniformly taught. 4. Not sure. Tossed, recycled or sold as souveniers, I imagine. 5. It probably aids with timing, a small measure of power, and intimidating the opponent. Mostly to do with timing the stroke though, I believe.