Customers lucky to still have unlimited data plans are putting it at risk if tethering. AT&T has confirmed that it will revoke unlimited data plans held by users who are using a Jailbroken iPhone for tethering. It will then lump its 4GB tethering-approved plan on the customer. The carrier has sent out warning letters to those tethering without a plan. @Yungjohnnybravo @TatWZA