The ban list is now active, which means people that are detected cheating on a secure server will be banned from all secure servers for 24 hours. We'll be increasing the penalty for cheating dramatically over time as we become more comfortable with how the system is operating. We know of no false positives being generated currently, but we're going to be extremely careful we aren't banning legitimate players.I'm sure some will complain, especially when the penalty for cheating becomes more than just a 24-hour inconvenience, so it will be interesting to see how things pan out. Since game servers are typically run by individuals who have long since had the ability to limit access to their servers, Valve should be standing on pretty firm ground. After all, the anti-cheating measures only apply to secure servers, and admins are free to run games where people can shoot each other through walls if they so desire.
Hopefully, Valve will stick to its guns and stay on top of the latest exploits, making playing Half-Life's various mods on public servers an enjoyable experience again. If Valve can succeed in largely eliminating cheating, at least secure servers, we may even see other developers pursue similar measures with their online titles.
Thanks to Shacknews for the tip.