I'm going to quibble with you on that, but I'll give you this: It's your only viable option.Well I have AT&T and I can't tether at all with my unlimited plan so this is my only option
I, too am grandfathered in to the unlimited, but you may want to look at T-Mobile's options, as they have a huge data plan that they get mad at something like 200GB/month ("get mad" means throttling), so that may work for you.
As for the quibble, there are ToS on those plans, and violating contract law does have its consequences, whether they dump you, or come after you for $$$ (I'm guessing it'll be the first).
There are ways around what is here below, but it's not that hard for them to tell who is tethering or not. What they do with that is kind of a mystery...
http://android.stackexchange.com/qu...-companies-detect-tethering-incl-wifi-hotspot
And I too use about 40GB/month, as this is my radio, and I listen to it as I work, or sometimes I'll listen to a movie while I work (It's a take my mind off of the jibber/jabber going on around me).