Meet the Ball Magnet, aka the invisible ball kid.
Stray balls during tennis drills are a nuisance, especially with groups of players or ball machine use. Errant balls that roll into the court take time to clear and then there's the safety issue. Kids in particular will play with balls all around their feet. This makes me cringe. I remember that pain.
The Ball Magnet is a nearly invisible tool that captures netted balls (80% of them) dropping them at the net for easy collection. You'll still be responsible for keeping an eye on back court balls.
Check out Ball Magnet's video below:
The current device is not useable for regulation USTA play but is fabulous for clinics, cardio tennis and drilling. I'm told the next generation of the product has been approved for tournament play.
It takes three minutes for an easy on or off. $279 will buy one for you or your club. Find it at BallMagnet.com.