Who is doing Food Swaps?

This upcoming event (https://www.thefoodstand.com/posts/14392-sallyrogers-summer-food-swap-in-berkeley-ca-city-of-berkeley) got me thinking more about food swaps -
Who has done them?
Have people found success with them?
Is this a good avenue/event to talk about food waste? I have zero familiarity with food swaps but I'm so curious! This site was a great intro: http://foodswapnetwork.com/what-is-a-food-swap/