It does in that if the real site properly stores a cookie that records that you've logged in from there before, the number of times that the user is asked for such questions goes down, increasing suspicion when the user actually IS asked for them.
Security is never about 100% guarantees. It's about reducing the exploitability and impact of weaknesses.
It mitigates a little. It should make you a little suspicious if the site suddenly starts complaining that you're accessing it from an unrecognized computer if you really haven't. I'd close the tab in that case.
