Channeling my inner "that guy" here: Make sure you call a T on the home team for the failure of game management to stop the kid before he got on the court. They could have at least tased him before he got there.
Seriously now:
If play had started coming your way, blow the whistle. Same as you'd do if there was a spare ball rolling on the floor.
Did Mom wait until play was stopped to run out and get her kid?