Really wanting to mod zombies but are worried about getting banned?
Well i have done the following things and im not banned yet!(6 is very important)
As far as i know, This is UN-Patchable but i have got some thoughts Microsoft and treyarch could do to stop these but I will NOT be releasing publicly for treyarch & Microsoft to see!
If you want to know and make a suggestion for another point PM me, i Will only accept from active users to make sure treyarch dont get there hands on the information.

1)Clear your HDD System Cache Every so often(DONT: IF ITS GOT MODDED GPD ACCOUNT ON/CLEAR YOUR USB SYSTEM CACHE...Will mess up profile).
2)Have all modded content on a USB Flash Drive and only have it Plugged in when you have your internet is disconnected.
3)When Playing XBL or Connecting to XBL Remove USB Flash Drive and Clear HDD Cache.(MUST DO)
4)Never Use GPD Mods online unless(SEE 5)
5)If a new BO XP GPD Mod is Released, Make a new 1 month account to host on and have a reliable friend, or another xbox, sign your personal account.
6)Before turning your xbox off everynight, remove the USB Stick w/mods on it, ethernet/wireless adapter/remove internet access from xbox console & clear system cache(Leaves no traces for night time ban waves)

Please Thank if this saves you!