All in all, not very spooky with Safari at least.
I assume (because mine didn't show anything) that it's relying on the browser leaking it's device-detected location without prompting?
After your comment I loaded the page again, and sure enough it shows a very specific, but quite wrong location. Wrong province wrong.
I actually got better GeoIP results than that (down to the local city) on my old broadband connection. I just tried it now (we moved 2KM and changed ISP, from DOCSIS to ADSL) and all I get is the country now - possibly because its dynamic whereas our DOCSIS IP never seemed to change.
So it's kind of creepy on Google's part that they even offer this service, but the data seems to be so woefully useless that I can't believe anyone would actually use it.