Wait a second...does this imply that if I put downloads that should only be of interest to our Windows customers on a server named something like downloads_.ourdomain.com, it might keep out all those annoying bots that ignore robots.txt and make a lot of noise in my logs? I'm guessing that most of the bots are not running on Windows.
That's a pretty bad idea, you shouldn't rely on this kind of stuff.
If there are people running OSX or Linux that want Windows downloads, or someone is behind a captive portal or proxy (like squid), they probably won't be able to reach it anymore.
If you have a real problem with bots, I'd look at what IPs they are coming from, and how often they try to connect. Something like IP blacklisting, or fail2ban might work for your use case.
