lucy24 - 8:56 pm on Jun 28, 2012 (gmt 0)
Two minds with but a single thought? :) (Note two adjacent timestamps.)
I was thinking the client could restrict his service to a narrow pool of users: students living in campus housing, and people occupying those overpriced housing complexes that come with everything pre-installed including Internet. That puts you in the rare and extraordinary position of being able to derive someone's street address from their IP address.
Not so useful of course if he's trying to target the entire state of Hawaii including outlying islands.
Time zone is really not a bad idea if you don't mind Polynesia and the Cook Islands coming along for the ride. And those are other countries, so you should be able to exclude them easily.