That's why I say it's theoretically possible.
And as for the Poland discussion, you could block a country at once, but what if a legitimate Polish user would actually come, do they have to visit a neighbouring country, just to edit?
It did occur onces to me, a video site has Blocked entire countries that were known to Hacking and Spamming, including, but not limited to, Russia, China, Japan, Ukraine, Poland, Netherlands, Mexico, almost all of Africa, Turkey (almost all of the Islamitic countries, actually), and many more.
But I told him how to do it differently (with better security), so he unblocked all of them since.