Every tennis tournament tries to do something unique. At the tournaments in Vienna, Stockholm, and a few others, ball boys and ball girls use a racquet with a net (looks like a fishing net) to pick up the ball.
Vienna has been using the racquet nets for more than 10 years. Even today, it’s not uncommon for TV viewers to be surprised at how these ball kids pick up the balls.
While it’s easier to pick up the balls by hand initially, once the ball kids get familiar with the fishing net, it’s probably more efficient.
Ball kids at tournaments are usually junior tennis players, who can easily handle the ball with a regular racket. But picking up the ball with a fishing net takes practice. I am certain that these tennis tournaments train the kids to use the fishing net effectively.