I had a friend that was banned from steam and he lost access to all his games. He claims he didn't cheat, but you'll never know.
Well here is my thing I wouldn't mind getting it through steam because its just friendlier than buying it, but what if one day they ban me for some stupid reason or misjudgment and I lose access. I heard there is no way to get it back so you pretty much lost your game.
First, no matter what you do, you can always play the games you bought on Steam(singleplayer, at least).
Second, when they catch you cheating, it's on servers with VAC(Valve's cheat detection) and it bans your account from playing on servers using that. Even then, you're still able to play the multiplayer, you just get booted from servers using VAC right away.
I'm not sure, but I doubt Borderlands will be using Valve's anti-cheat system.
Well, after about 6 months of hacking on CS 1.6, I finally got banned. But all it affected was HL1 games. HL2, all HL2 mods, and all other games are fine. I'm not even VAC banned from anything else besides HL1 games.
And if anyone was wondering, yes...knifing an entire team of 16 people in their spawn before they could even buy guns was well worth it! :P
Your Steam account ONLY gets a full ban from EVERYTHING if you use a credit card that is stolen or reverse a transaction saying that you didn't make that purchase. Claiming ID theft and stuff like that.
Those are about the only ways I know you can get banned completely. So your friend did one or the other and then it's completely HIS fault.
if borderlands is your only steam game they cant ban you from it, you only get banned if you cheat online in VAC servers (or as someone else said doing illegal stuff like stealing credit cards or using a cracked version) which borderlands doesnt use