Green Day is as punk as Nickleback is metal.

(I know it’s gate keeping but I can’t help myself)

They uses to do "knowledge" by operation ivy regularly. The bands were old friends from the east bay punk scene and the cover was like a tribute. A 3 chord banger that anyone could play and the crowd would get into. It was really cool when younger audience members were able to learn it on the spot and then the band backed them up.

You're gonna be the bum that shaves me

My understanding is that it's the Rickroll of the guitar-playing world.

It's fairly straightforward for the novice to play, and is associated with the hipster who lugs a guitar everywhere as a fashion accessory rather than to develop any musical talent, where their repertoire is limited to two or three four-chord wonder songs.

In this instance, the guitarist has given the audience member the chance of a lifetime to shred in front of a crowd that most amateur band members will never see in a lifetime... and instead threw out the "so anyway here's Wonderwall" meme and dropped a simple meme song.

Happy to be corrected.

The band Green Day invited a fan up on stage to play one of their songs, but he played the song Wonderwall instead as a joke.

Guitarists playing Wonderwall for people has been a meme since the 90s. Here's more about it if you're interested:

https://knowyourmeme.com/memes/wonderwall

Full article: https://archive.is/8GyPF

Basically the fan tricked the band and he was stopped because he wasn't playing the song he said he would play.

All in good fun I think, they seem very chill on stage

It's against the rules!

Due to the lasting popularity and easy chord progression of the song, it has been cited as one of the most frequently covered songs in the recent history of contemporary music, while equally mocked for its cliched nature and textbook status among novice guitarists. It's also associated with the meme and catchphrase "Anyway, Here's Wonderwall."