I've not encountered this regularly, but I think I did see it in a very specific circumstance a few years ago.
I sometimes visit the forum at lunchtime from my work computer(which is in the same time zone as my home computer).
One time on a travel assignment, I was remotely logged in (Windows remote desktop) to my computer at my desk from a location a few time zones away. I believe I saw this banner pop up at least once in that case. So some characteristic of where I was actually accessing the internet from might have caused this. (keep in mind I was using the same installation of the browser, and the computer I was actually running the browser on remained in the same time zone as always.)
Even this is a bit curious to me though, as my regular connection at work (to other websites) is seen as if it is not local geographically . If I go to a big box store website, it may assume I am in a different region of the country when it suggests what my local store is.
The point of all this is, I'd agree that it can be a bit of an odd combination of elements contributing to whether you see this or not (relating to both your PC and also factors relating to your ISP that you have no control over and may be transparent in most other cases) . It's not necessarily just a simple "check the timezone on your PC and also your Forum profile" issue (though I am sure it helps to have that correct too! 
)
-Dave
