Don't think there is any way of getting the stats on where people live automatically. At most they would probably be able to get most commonly used locations, as a IP belongs to a location, but that doesn't mean that the user lives there (or even that the user is physically around there [VPNs], but probably usually right).
IP data would be close enough to the actual aggregate proportions
Given how many people browse HN at work it would be super skewed.
Let's test it
Correct. You'd get a lot of people who suddenly seem to live in Columbus, Ohio or other random non-tech spots within USA due to AWS VPN and other such things.