Ping pong balls are useful for several things – playing ping pong (of course), cat toys, playing beer pong, bingo balls, juggling balls and science experiments.
but….I saw a new use for them recently —- as crowd control in a supermarket! Sweden does not have lockdown but they do strictly restrict the number of people allowed in shops. Only a certain number are allowed in at a time. Usually there is someone standing at the door, limiting entrance. They manually count the number of people going in and out, but this is difficult if a shop allows hundreds of people and there are several entrances.
At this supermarket entrance I saw a giant basket of branded ping pong balls next to the baskets and trolleys. There were 160 people allowed in the shop, and 160 balls. Every person going in took a ball, which they placed in their basket. When the balls were all gone from the basket, no one else was allowed in. The ball was taken back from the customer/s at checkout, disinfected, and returned to the basket, allowing more people to go in. I am not sure how well it worked but I was really intrigued.