Yeah but this is the simplest way of preventing it without having to add a feature to the game and waiting on a new build. Yeah I see what your saying about the disconnect in a sure cap situation for the other team. They do not get 5 pts before the disconnect, and the other team still gets 3pts., while they get 0 pts. If your team had the flag as well as the other team having the flag, why would you disconnect to take your chances away to get 3 or 5 pts, its just not logical to give the other team 3 pts. unless its in a tight game and you already have the lead with a min or 2 to go. Which then would you really want your team trashed on the forums for disconnecting in a tight game? Its really not a huge change to the CTF dynamic as the object is still to cap the flag. I also think it adds more skill to the game. As no longer can you just strategize getting the caps the fastest, you have to strategize to protect your flag and also get the other teams flag at the same time. Though if we combine this feature with password changes at the start of the match, this would let the team in control of the server have the ability to tell the members the new pass.
So there is really no quick fix, we could come up with a hall of shame for these clans that do this. I mean you couldnt just go by someones word. I mean if they had a demo or a screenshot of the offense, as this poster does, then the clans would be added to the list. It is not right that clans do not get punished for such behavior, even if atm there is no way to prevent it from happening.