Did some more Steam sharing testing. I took a game from my buddy’s list on my ok’d computer and tried moving it to another PC using my same account to see if I could get it rolling.
First method I tried was packing it up using the “Steam backup” feature and then installing on the other machine. It recognized the installer but asked for a CD key to unpack it. No dice.
Second method was moving the game directory and .acf file to the appropriate folders on the other computer, then starting Steam in offline mode (Which is usually how I move crap around on my local machines for Steam anyway). It DID recognize the game and showed it on the list, but under the “Unrecognized source” categorization and refused to launch. If I started Steam in online mode it would correctly label it as “Bruticis’s library” (Which is what it would on my main PC) and show the game, but it wouldn’t launch and the only option it gives is to purchase the game.
Summary, even though the glorious god-Gaben is generous and lets you play shared games in offline mode, you can only do it on the machine that was ok’d for it in the first place. Without resorting to actual cracks and shit of course. But if you’re going to go that far you may as well go full pirate.