If any of you have ever played Half-life/a mod of Half-life, you might recall a list on the host's computer of WonIDs (unique number to every player) who are abusive, cheaters, lamers, etc. But since in AH it is difficult to change your game ID, this list would only hold names, not numbers. So when a host bans someone, (maybe a .ban xxxxx) it puts their name on the .cfg so if they try to rejoin the server, it will not let them.
Just an idea for maybe 2.10 or some future version since, if I recall correctly, they will not be adding new features for 2.0 that haven't been already.