[nosideeffects]

I thought it only showed this information if you had recently, successfully logged in to your account on that computer?

[ic-junk]

Yeah I suppose that is possible if they didn't spoof it or your device becoming compromised. I haven't seen/read anything on what they're doing to handle this scenario.

[ucaetano]

If your device is compromised, someone knowing which accounts your have is pretty much a given regardless of you logging in to Google...