i remember reading about a guy doing that on sythe, gm basically told him they had no evidence so tough lol
Never Wintrade.... - Sythe.Org Forums
I think in all honesty its a risk, it'll be a lot more hassle to remove achievements that's stamped into your bnet account then it would to just ban hammer you. You could do as 4096 said as it does hide from the armoury also (my rogue shows as 5k points when my main has 18k+) but if the character you wintraded on is the same one you're playing then its not much use, maybe level a new mirror class and start from scratch.
Personally i'd just say it was the season where wintrading was rampant, you met loads of ghost teams whilst playing legit and were fed a lot of easy rating. Most people know last season was madness for it and even the legit people get called wintraders.