Late last week I started getting emails from Modern Warfare 2 players who claimed their Steam accounts were banned for alleged cheating. It turns out that the problem was down to Valve's own anti-cheating software.
It sucks to be accused of being a cheat, and sucks even more to have your account banned because of it. However, Valve president Gabe Newell seems to have done the right thing by unbanning the accounts and offering a free copy (and one to give away to a friend) of Left 4 Dead 2 to everyone affected.
Recently, your Steam account was erroneously banned from Call of Duty: Modern Warfare 2.
This was our mistake, and I apologize for any frustration or angst it may have caused you.
The problem was that Steam would fail a signature check between the disk version of a DLL and a latent memory version. This was caused by a combination of conditions occurring while Steam was updating the disk image of a game. This wasn't a game-specific mistake. Steam allows us to manage and reverse these erroneous bans (about 12,000 erroneous bans over two weeks).
We have reversed the ban, restoring your access to the game. In addition, we have given you a free copy of Left 4 Dead 2 to give as a gift on Steam, plus a free copy for yourself if you didn't already own the game.
To share your extra copy of Left 4 Dead 2 with a friend, you can 'Manage Gifts and Guest Passes' from the 'Games' Menu in Steam, or visit this article on the Steam Support site for detailed instructions: https://support.steampowered.com/kb_article.php?ref=4502-TPJL-2656
To access your own copy of Left 4 Dead 2, visit your library of games in Steam. If you didn't already own the game, it will now be listed among your others there, and is available for download immediately.
Regards, Gabe Newell President, Valve
[UPDATE: Just heard from a Valve user who wish they had been banned so they could get their hands of a free copy of L4D2 ... I guess there's no pleasing everyone! LOL Goes to show how good Valve's PR machine is at dealing with these issues.]