From the guide:
There have been reports of a wave of bans being handed out to CFW users by Nintendo. To protect yourself, please do the following steps before starting this guide:
Go to System Settings, then “Internet Settings”, then “SpotPass”, then “Sending of System Information”
Disable the “Sending of System Information” option
Exit the System Settings
Go to your Friend’s List (the Face Icon in the top row of your Home Menu)
If you receive an error and are kicked out of the menu, the Friend’s List setting is already disabled
Go to the Friend’s List settings, then “Friend Notification Settings”, then “Show friends what you’re playing”
Disable the “Show friends what you’re playing” option
Exit your Friend’s List