We have just wondered if we should take disconnects as a part of the gameplay mechanics.
Since they introduced the disconnection rate it has lead to various "tactical DCs". Thanks to smart DC management one can lift her or his rating and carefully while protecting their ranking against weaker player who get lucky. You have to estimate the average DC rate and then try to keep yours lower than average + 10 as well as the rate in which other player DC on you. That way you keep a bit of leeway about how far you can go without being excluded from the ranking.
Of course, it is still a dick move but it takes the "play-to-win" mentality to the upmost extreme and is legal until you have gone too far. Tournament player should win by any means, are we right?