Turn inner tubes into a bouncy seat

I thought this was funny, the author took some old bike innertubes and basically made an under 100 lb bouncy seat with them.  Cool idea but you may want to wash the tubes first to keep your clothes from getting junk on them.  I wonder if you double them up or put them on a board if you could increase the weight limit?

http://www.instructables.com/id/Bicycle-Tube-Bouncy-Seat/