Allowing it in CS1.6 would make it much harder to keep it out of Source. That exact argument has been made before.
The problem with CAL’s stance is that it is a typical CAL stance. They would rather allow something they know is controversial and tack on “so long as they aren’t cheating to do it” than flat out ban something. The problem is you can’t tell the difference between someone who’s legitimately good at it and a scripter, and of course the script kiddie is going to say he’s doing it without cheating. That leaves the admin in a precarious position, having to second guess himself on whether or not to kick someone, knowing full well he’s probably cheating.