Not trying to argue anything, but this is a complicated issue that I haven't made up my mind about.
It seems inconsistent with the VAC ban policy UGC and ETF2L have to let proven pub cheating go unpunished. It's easy to forgive someone for hacking in a pub months ago, and certainly it doesn't make them ineligible to compete. I just don't think it's fair if someone gets off completely free with admitted cheating. Simply put, cheating in a multiplayer environment is wrong and should be punished in some way.
9.5.2 Source Engine VAC Bans - A player with a Source Engine VAC ban (that prevents the player from joining a TF2 VAC secured server) will be banned from the league for a period of 6 months from the date the account is VAC banned. In all cases, the ban period applies to a person and not a single Steam account. Alias accounts created to evade this VAC policy will lengthen the duration of the player ban.
ETF2L has a similar but harsher rule
6.5 VAC Bans
As of March 15, 2012, any player with a VAC ban on the Source engine will be banned for 1 year. Players with VAC bans that do not apply to Team Fortress 2 will not be affected. Players receiving VAC bans before March 15, 2012 will not be affected.
Any proven cheater should be treated as if they're the not-so-proud owner of a VAC ban, otherwise we're saying "go ahead as long as your cheat is undetected". And we all know how common undetected TF2 cheats are. The purpose of the rules is to show that the competitive community of UGC and ETF2L does not tolerate people who cheat in TF2, period. I think it's important for all organizations to be willing to put their foot down against cheaters, since Valve has not been effective at this. UGC is trying to do its part to keep TF2 clean, not just the league itself.
These rules have been in place during the alleged offense, and Hassassin appears to be in violation of the intent of these rules, even without an actual VAC ban. At the same time, there seems to be plenty of reason to believe his competitive career is squeaky clean. Not sure what the appropriate action here is, but doing nothing doesn't sit right with me. Input is appreciated.