Actually... some people use a "similiar" technique for blocking sites they have no desire to ever talk to - though it's usually done at the router level. It's called null-routing... and it's usually a decent response to areas of the world who perform routine port scans or more blazen approaches at trying to break in to a box, etc.

In fact, there are a few links out there of suggested "blackholes" (ie. null routes) to add to your firewalls and/or routers. Here's a link to (the intro of) one of the better ones (it's autoupdated with offenders listed in many different router logs, etc):

http://www.dshield.org/block_list_info.html