When a player disconnects when they are losing, I wait till the server times them out -- then I leave a note on their homepage about their poor sportsmanship to warn others. It ain't much, but maybe it will help to discourage this habit.
I don't think these messages help at all. For one thing, they can just delete them. Another thing is that I doubt most people look at someone's profile within that 30 second time for the auto abort before the game starts.
Pen2da_Pixel also has a point.
Before posting a comment about someone disconnecting when losing, I go to their page -- about half already have similar comments already there. That helps me, because I see a pattern of disconnecting. I block those individuals.
If you do not think that the idea is worth the time, just don't do it. However, I am always interested in hearing alternatives.
I normally just wait until he is timed out and don't do anything else as you can NOT be 100% sure of what happened. Sometimes I get disconnected and can't get back on fast enough; it is bad enough when you are loosing; sometimes I get disconnected when I am ahead and winning, now that's a killer.
I find it interesting that these people keep these comments on their page. Sure, some are just a few hours old and might not have been seen yet, but usually they are days or even months old. Perhaps it's a badge of honor for Jerk Scouts?