This speculation is 100% wrong. I checked for this app after seeing this and had it listed under updates available (it was installed already)

So I decided to check if I was in fact opted in and I was not opted in. Everything was off and this app was still installed without my consent. I do have automatic UPDATES turned on, but that shouldn't tell Google to just push whatever they want to me. You should probably edit your post saying your speculation is wrong.

I don't know what kind of proof you want, but I 100% never opted in.