Unauthorized Tethering

The wireless and phone service companies figured out yet another way to charge more money. When the unlimited data plans rolled out, it started out like a great idea but then they realized that they are losing money because people are tethering their devices to the smartphones. For those of you that are not well versed in the tech language, tethering is when you connect devices to your phone's internet. People who connect their devices like that, obviously use a lot more data than others. This slows down the connection is many people are doing it. So the wireless companies decided to let people do it, but for a fee. Is it me, or does it seem like people are being charged for data twice? The carriers can usually tell if you are tethering if there is a lot of data that is being used. One of the ways to be able to get away with it is to not use too much data and use an unlocked and unbranded which means that it is not using carrier-supplied "firmware". What are your thoughts about the tethering charges?