Need a volleyball-proof infant shelter?

My friends host a weekly volleyball game and would like to set their baby next to the court while they play, but they're worried about him getting hit by the ball. So they're looking for a protective shelter they can put near the court.

It has 2 requirements:

1) It must protect the baby from the ball, even if it's hit hard right at him.

2) The baby must be visible to the parents while they're on the court.

This is an indoor game, so the shelter doesn't need UV protection or sand anchors, but if you find something designed for the beach that's OK too. They can adapt or modify it if needed.

Any suggestions?