[quote name='DarthPuma']But achievements have nothing to do with it. It's been a month or so before I've read up on this, but last I knew every time you play a game it records onto the NAND (I believe that that is what it's called) chip in your 360 that you played the game, whether you are online or not. It also logs if there are any DMI errors or errors like that.[/QUOTE]
I was just pointing out that it can't log the date and time you play accurately, specifically in regards to manthing's comments.
It was more of a "you won't get banned because you got an achievement before said date if you play offline" than a "you won't get banned if you play offline, period".
If something looks funky with a disc, it's entirely possible they could nail a modded console that only played games offline. Is it common? Not that I know of. Could it happen? Probably. (It's the difference between mygamercard.net and live when it comes to ordering your games. MGC checks the "last played online" field, while microsoft notes the order you play games in, online or off. Thus, if you play ODST before release and then decide to log into live with your gamercard to play a game online or download something, live will still have it in your gamercard as played before release.)