Usb Tethering and Unlimited Data Plan

I don't work for ATT.  I'm not a lawyer, and I don't care to dicker policy with you.

ATT has the right to sell you service with rules attached.   The FCC agrees.

If you get caught, they have the right to terminate you plan.

T-mobile went after customers breaking the tethering rules.  

You can go round and round and it will do no good.  I prefer sudoku puzzles, but if this is the hobby that floats your boat, have fun with it.

It does not allow this, at all. It allows for transmission of data between devices YOU own outright. Your computer. Your routers. Yes, your phones but not over the CELLULAR network. You may transfer all you want over WIFI, BLUETOOTH and even through USB but that does not include CELLULAR data. You can modify all you want to move files from your computer to the phone, when it does not involve accessing the celluar data network.

Customers do not own the network. It's a privately owned entity. Circumvention of the tethering restrictions is a violation of AT&T's terms and policies. The DMCA does not apply to the towers, VLR/SGSNs, internet backbone that you as the customer do not own.

Unlimited data is a table with one seat. All data is not equal via cellular. The phone facilitating the data transfer does not mean it's the only device using it. Sharing with another device means you are adding an addition seat to the table. T-Mobile's CEO had an interview a few months ago where he torched a bunch of users who were getting around their tethering policies. The carriers can, and will, cancel someone's service who is violating the terms of usage. 

@waynelroberts They have plans where the bits are just for one device and plans where you can tether (share the bits).  People who tether probably (generally) use more bits, they use them on their phone and their tethered laptop/ipad.  Full screen video is a lot more enjoyable on the 15inch screen than a 5inch screen so you'll watch more, that costs them more.  

They could just charge everyone for the most expensive plan and assume everyone will tether, but that's not what they do...

They price things based on use.  Unlimtied people do not use unlimited data, most probably don't use any more than the people with a 5GB or 10GB plan.  

On 700 minute phone plans, no one made exactly 700 minutes every month to get their highest value, AT&T  counts on that and prices accordingly....

The real issue is signing up for a plan doesn't have tethering and then complaining the plan doesn't have tethering...