I think I might be talking to a brick wall here, but I will try anyway.
Look, DLC & Mod's are not the same process, even if you can describe what they do as both "modifying" your game, thus the end result being a modification to your game in both cases. Mod's are free modifications that will be available in the mod browser, DLC are paid modifications that are available in the Steam store. This is the key difference, Steam will have nothing to do with the mod browser and all the mods it includes inside, including a mod which is a copy of a DLC "mod". Thus Steam
HAS NOTHING TO DO WITH MODS. or "mod's from the mod browser" if you want to be specific on the meaning of the word mod.
Just because you "can" define DLC as a "mod" of sorts, doesn't change the fact that "Steam has nothing to do with mods" statement is correct, perhaps it needs to be clarified simply to say "Steam has nothing to do with mods from the mod browser". This is what Greg was reffering too, redifining something else and then claiming that Greg was wrong all along and thus invalidating his previous statement about the other type of mods has no basis in reality.
Steam may however act as a DRM stopping you from outright copying any Steam files, this is its job, it won't however scan your game for Mod's from the mod browser that are copies of DLC, as stated it has nothing to do with the Mod browser, thats not to say such "DLC copies" will be allowed to exist very long in the mod browser if they are modded by someone, but whom ever said "moderator" of the mod browser is, it won't be Steam.
Perhaps I have broken the through the bricks on your wall to your logical thought processes, perhaps I have failed, I will endevor to use a bigger hammer next time if thats the case.
As for "I didn't realise you were the forum mod", well Greg isn't a mod as far as i'm aware, and you don't have to be a mod, or in an offical position at 2k to have knowledge. I have knowledge and I'm trying to pass it along to you, but obviously you are one of those people who can't be taught knowledge, or perhaps you are, time will tell.
Yes, this was very similar to my original question. My wife and I often play Civ IV together on our LAN at home. Are we going to need two Steam accounts for this to work? And, if so, does that mean that we need to purchase two copies of Civ V? That would be quite unfortunate...
Da Rabbit
In the FAQ itself it states "LAN will be available in offline mode". Now as others have said, you can have an unlimited number of computers logged into "offline" mode on the same account, so will you be able to have 5 (or two in your case) computers all in Steam offline mode using the same account playing LAN together, yes. This is good for you and others who like you dont want to purchase more than one copy but still use it as if you did do this. Personally I would have prefered they limit LAN mode to "online" mode to remove this "loop hole" where you can avoid buying more than 1 copy for you/yourfamily/allyourfriends and so on. However if they did, they would have removed the few cases where several people want to play LAN together genuinely each with thier own account but somewhere where with no internet access.
The whole "using multiple offline versions of the same account" is against Steam EULA policy, so don't advertise the fact you are doing it to Steam or they will likely ban your account which will lose you your game.