Ok I spoke too soon (my specialty apparently) according to one of the comments from someone named u/trooth you would agree to the app:
“It’s an app event organizers can use to create a prerecorded phone light show. I’ve seen them in smaller venues before. You have to download the app the QR code sends you to. It doesn’t take over your phone automatically, you choose to download this app.
Edit : I found the names of the apps they could use for this. CUE Audio,Crowdr,CrowdGlow or Smartphone Light Shows”
But also, fuck this lol