I am an Ubuntu 7.10 (Linux) user, wishing to run legitimately bought games using Punkbuster. I use Wine to run these Windows-monopoly-tied-in games on Linux, which works perfectly with graphics and everything at native speed. The only thing preventing me from using the games is that I am repeatedly kicked from servers because Punkbuster performs MD5 checksums on my API files and kernel checks, which fail because Wine's code is nothing like Windows. Though I have no intention of cheating, it is Punkbuster alone that is preventing me from enjoying the games.
Punkbuster discriminates against those who wish to avoid Windows as a personal preference. There appears to be no intention from the developers of resolving this, and thus they are missing out on a small but significant market segment.