Sounds like a great idea.

How do you differentiate between one person using multiple accounts to cheat, and 2 people using the same computer to play?

I don't want to sign my brother up from the same computer, join a few team games with him, and somewhen in the future get both accounts banned for cheating.

It's essentially impossible to differentiate at the server level (i.e. from our end) between two different players using the same computer. However I don't think the problem is necessarily with team games, it's more with single player ranked games where one person uses a separate account to boost the chance of their other account winning the game.

The only way to pick this up is for players to spot something fishy going on and report it to an admin. Then we can go back and analyse the history of the players in the game to see if this has happened in the past. If so then we can ban the duplicate accounts.

So in other words it has to be a community driven action to weed out multiple accounts and it will be actively supported by the admins.

That sounds good. We were always very careful on that 'other site' to avoid being in the same single player games, so as long as it's not an automated thing then I won't worry about it.

On the 'other site' the admin didn't care when people were blatantly cheating - (ie. Phoenix) In multiple documented games, all of which the admin saw, and verified as cheating, and said "Well, that player doesn't seem to be playing as much anymore, they'll eventually drop off the top 10" and that was the end of it. Pfft.