This is why I always ignore these headlines until I see the change firsthand. In this case it wasn't even an article, only a brief forum comment, for a topic as complex as spam protection. Might not be an A/B test, could just be someone with a low-trust profile (eg Arch Linux ipv6 in Singapore with multiple Gmails).

Well, a headline that states that “Gmail now requires scanning a QR code for some people some of the time” is not too exciting.