This is by far the most atrocious example that I have seen as of yet regarding tethering using a jailbroken device.
Here is how I see it, and 100 to 1, people will probably see it my way.
Data = Candy
I paid $1 for a piece of candy. But if I want to eat that candy with a fork or whatever other utensil, that will be another $2. AT&T is doing the same thing. Users who pay for the 200mb, 2gb or 4gb tethering plans pay for that data. They aren't stealing it. They use it how they see fit. But AT&T wants to charge you to use it on any other device aside from the mobile device that receives the data initially. I am sorry but I will pay for my candy but if I want to eat it with a fork or melt it down and lap it up with a spoon, that's my prerogative. End of story.
Now I understand why all the telcom's are pedaling backwards to tiered data. 5 years ago with unlimited data, there was no iPhone, no Android, no big deal phone that could suck up data by the gigabyte. But there is now, and the telcom's now realize the error in their ways. People loved the unlimited data because they never had to worry about going over (hense why we have rollover minutes and unlimited texting and unlimited everything else). And with data hungry devices coming out to market month after month, more and more people worried about "going over" the telcom's are looking for an exit strategy. Tiered data. Basically says, we know your device sucks up data by the motherload. So we wanna cap you off. This is fine, for those who are actually in tiered plans. But for those of us on unlimited plans... hands off, were keeping them for a reason.
In the meantime, some will switch to official tiered tethering plans, others will switch carriers, others will stop service, etc. Eventually the numbers of unlimited data plans will dwindle to a small fraction of the subscription base and the network traffic will be tolerable. But in the meantime, nobody is stealing data if you PAY for it and use it how you see fit. Bits are bits. Stealing data is getting data access and not paying for it, or walking into the store and taking the candy bar without paying for it.