You probably know this already, but AT&T relies on most customers using nowhere near their data cap each month; allowing tethering would significantly decrease

You probably know this already, but AT&T relies on most customers using nowhere near their data cap each month; allowing tethering would significantly decrease their profitability. They can make a profit from someone who uses 5gb and pays $55 in a month, but I suspect they make more from someone who uses 400mb and pays $25.