Adding a phone number to your Google account can make it less secure
> I'm curious [...] why Google doesn’t temporarily disable accounts so impacted until a human reviews activity.Because Google doesn't have humans reviewing anything unless there's a direct link to marginal revenue/cost avoidance attached to that interaction that can be priced in. Their business model is to achieve scale through automation and machine learning; which means not doing things that would require manual intervention unless absolutely required.Explicitly, this means that for free services like Gmail, humans aren't involved. Ever. Try getting support for a Google product and you'll see what I mean -- there's not even a phone number to call or an e-mail address unless it's a paid product (and even then, they've got a less-than-stellar reputation for support of paying customers).