I posted this in another thread, but in order to get more people to read this, I'm making a thread specifically for it.
This is how Blizzard Serverside checks for MC.
They apply a Z-Axis boundry to certain areas of the game, which no chracter should legitimately pass. When this boundry is crossed, it flags the account for investigation, which then usually leads to the ban.
Even if you bypass Warden checks somehow, you can NOT stop serverside checks from happening.
If you don't want to get caught with MC, don't climb anything you couldn't fall from normally.