I have "unlimited" with no tethering also.
The unlimited is rather misleading in that my iPhone 5 is effectively unusable for data past 3 gigabytes with the throttling policy in place.
So AT&T will probably win and force me into a $20 more expensive data plan, but at least the device will be usable above 3 gigabytes. Hotspot could be fun, also.
Thank goodness I own some T and may perversely benefit from their increaased income. :smileymad: