I understand many people will comment that you cannot get banned for iso modding or it's a low risk of Ms banning you.

Here's a few steps to slim the chances to ZERO.
Step 1.Use the hotswap method to install the modded copy of Call of Duty:WaW
Step 2.Boot modded copy off HDD.
Step 3.Change your online status to away which makes MS moderators believe you are not at your Xbox 360 Console.
Step 4.Start up Xbox Live Nazi Zombie Lobby and invite friends.
Step 5.Once ready start game and while it loads switch online status to appear offline. This makes Microsoft lean away from watching your activity leaving you with a lower ban risk.
-Thanks zVaLoRx