[quote name='HeSaveDave']Wouldn't their system be able to detect those things as soon as you connect? Hack your items, connect, system sees it, ban?
I agree, having them completely separate would be perfect.[/QUOTE]
Detecting such activity is much easier said than done. When the user's offline, the game would have to save something somewhere detailing either what happened in the game/what processes were running on the computer/if there was any RAM data accessed outside of normal operation procedures/whatever else Blizz could use to identify an offline hack. Moment someone finds these logs and figures out a way to modify them such that Blizzard either the logs don't send up a red flag, they're screwed. Sure, it could take some time and a bit of work, but considering there's money on the line, you can bet people are gonna try till they succeed.