You literally just described fraud protection, which is something most banks nowadays use. It might be opt-out (or even opt-in) but that's very much a thing that banks do, and they get plenty of false positives with it.

I'd rather have my bank abruptly close my account for opaque reasons than fraudulently open additional accounts in my name.

Why not both? With Wells Fargo you can have it all!

Well...latter is illegal and the former isn't (usually) so I think there's a bit of apples-to-oranges, but yeah you got me, as we've seen being a regulated institution isn't a guarantee of good behavior. I still think the incentive, opportunity and the inclination of Google to not act in my interest is pretty high.