Ok first! do the rec centers furnish balls? Fine this odd if they do or is it included in the amenities fees? Usually in racket sports you furnish your own rackets/paddles and balls. If the Rec center furnish them who signs them out? And how long can the be signed out?
Now for the people that left the court with the balls? how did you know they were furnished paddles and balls, are they marked?. Maybe they had they're own balls?
I would think that Rec center person who's responsibility of equipment would know the details of who had the balls and for how long they could keep them and if they gave up the every last ball. If so sounds like poor ball management IMO
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