Some hackers control lobbies and matches, and sometimes they have the ability to pass abnormal abilities onto other players... in your case, one had given you certain advantages... and in this case you picked up a 'God Mode' hack from one of them... in the same fashion, they can add extra XP to give you an abnormally large experience point bonus per kill, they can give infinite ammo so that you don't run out as usual or have to reload as often if at all, they can make you run faster, they can make your character invisible, they can make you hold more than 2+ tactical grenades or multiple frags/semtex, even more than one throwing knife... some will give you two guns (not normally 'akimbo-able') such as dual MSR sniper and the like... trust me I have seen it all and I have been on servers with ridiculous crap such as this myself... and probably why BurtonJ of Valve once told me on my old account that I was operating a hacked Chaos lobby (page 2 of this post):
Though you did not run any 'illegal' software (or maybe someone else downloaded it while you weren't paying attention? *it is a possibility*)... anyhow YES, some types of hacks CAN be passed on though you are not running the actual aimbot or wallhack software, making it seem like you ARE THE PROBLEM, when you are truly NOT THE PROBLEM. Sadly, nothing you can do about it, except either attempt to locate the true hacker(s) and report them... however in cases like this, most often I myself find myself leaving the match/lobby prematurely before the match is over since this is NOT how I intend to play and do not want to participate in someone else's dream world. Sometimes, I'd love to stick around and identify the problem, yet I was banned on my old account with 1100 hours and at the time down to rank #367 in CTF leaderboard... and no way in hell am I going to suffer losing my stats again to BS after I worked hard to put up 2300+ flag captures, 3500 returns/defends, and 37,500 kills... still attest I never downloaded that crap and probably had the same 'passed on' abilities which I have seen on the new account multiple times since then... and if it can be identified, maybe it would clear my name once and for all, because hackers have done the same to me on more than one occasion... I don't even care that I spent an additional $40 for a new copy of the game, nor do I care that I bought the DLC all over again... but this same crap is what I believe caused my ban and stats reset (as it most likely earned my multiplayer ban 'cheating infraction')... I pray that doesn't happen to you, because there have to be 100s of players that can attest this is 100% positively truthful that they have also had abnormal abilities passed on by the lobby host or hacker in their match, giving an unwanted advantage in your gameplay.
EDIT: 'old account' has the same name in Steam - badplumr - a.k.a |APU| n00b (ingame name, formerly |ANI| or |APU| PiMPiN AiNT EZ, also no longer logged in *last 3+ months ago or so to search for an old friend's profile link*)- and the 'new account' is: lovethyplumber - a.k.a. [AR]PiMPiN AiNT EZ (just for clarification, if anyone wanted to verify... and renamed so as not to confuse other players and friends because I don't want to directly associate on the terms that I was awarded a ban due to a 'cheating infraction')
Message was edited by: badplumr