Sort of? There’s signage asking people to clean up the parks, and there are official volunteer projects (unpaid) to do park cleanups. I’m acting on my own on my own time.
For something more directly relevant, my city has an official “fiber ambassador” program for the upcoming muni fiber rollout, and they are actively seeking unpaid “fiber champions” to post signs and tell friends about it. I didn’t do that (don’t want an obligation), but I do hype it up with neighbors and whatnot because I’m excited about it. The fiber program won’t be free, but it should be very competitive with existing infra (we have a local fiber-backed ethernet ISP, cable, dsl, and fixed wireless). If the city approached me and tried to pay me for that, I’d turn them down and probably champion it less because I don’t want the city to bother me.
And the situation in the article isn’t even like that “fiber champion” program, it’s just an invitation to meet the team. There’s no on-going obligation, just an invitation for a special event for people with an outsized influence on the community. It’s more of a “thank you” than an agreement to keep doing it.