Soccer is a pretty big waste of time but I can't see how keeping the shape of the ball a secret would stop them. They already do play with balls cut out of other patterns sometimes.
There were lots of other shapes in the atomic bomb, are the others evil by association too? The first runaway nuclear reaction was inside a cube, why weren't cubes kept a secret?
Personally I'm planning to keep drinking water even though it is a critical component in every nuclear reactor design.