Hi,
I do actually agree with you on this one, this type of thing should be penalised.
Having said that - your ranking is there to help you work your way through the different tiers eg Hack, Amateur & soon Pro. Its a ranking you can use to improve your own game. In itself though - the ranking doesnt really mean that much. So people who cheat by disconnecting etc etc just to keep their ranking up, or down are not really achieving anything.
As I think Tibbetts has previously mentioned, ranked rounds, multiplayer games really are just for fun & practice. Its in the tournaments where it counts, and there - your ranking only indicates what tier you play in.
So - annoying as it is, dont get to hot under the collar about things. These guys are only fooling themselves, and in the end - if you cant play to your ranking whats the point of it all.
Cheers Doug