I just saw vanhanh.pham in top 5 of round 271 and remembered that he won another Div 2 round in the past. Then I found his performances quite "interesting". You may want to check his submissions in Div 1 rounds.
Although it is completely legal to do this, intentionally (I really hope that someone can prove me wrong) dropping rating to participate in Div 2 rounds officially is such a shameful behavior. I'm pretty sure I know his real handle and he has no trouble with staying in Div 1 (became red). How does he not know about unofficial participation in Div 2 rounds? * sarcasm *