I know people who have used close to that tethering on Verizon with no capping or throttling. I personally have used around 70GB in one month testing on my HTC Thunderbolt 4G.
I have used 40GB last month on AT&T tethering to my Samsung Infuse 4G in a "4G" area with no throttling as well.
Data cards are another thing though, of course if your not on an unlimited plan you will get charged out the wazoo.
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