I live in Israel, but I have a site in Russian. We have lots of russian-speaking people here who use google.ru (in russian Windows) as opposed to google.com or google.co.il
I created a PPC campaign in Google Adwords with a goal of targeting Russian speakers in Russia and the Ukraine (but not here!). Therefore, I just added Russian Federation and the Ukraine as the ONLY 2 countries where my ad should run. And it does work, generally speaking, BUT... when someone in ISRAEL who has Windows in Russian AND who goes to google.RU types in Russian certain phrases, that triggers my ad to appear, unfortunately, and I waste my money. I thought about an IP banning, but that probably won't work, since (from what I understood) you can only ban so many IPs (basically very few single IPs and banning on a whole country scale).