So I pay Charter for my internet service... That means I pay for internet on my MODEM and not on my computer, PS2, 360, Blu-Ray, TV etx. etx. etx.
Your statment does not make sense. in this scenerio the PHONE is more like a MODEM. It has a chipset that acts like a modem, your phone acts like a computer ans Safari or any other app is the software.
You're wrong. Your phone is a phone. AT&T and Verizon price your "unlimited" data plan based on what you consume with your phone -- not all the devices you can conceivably connect to it. $30 bucks gives your phone an unlimited data allowance. Keyword here is phone. It's not that hard to understand.
However, if you pay for a specific allotment, I do agree that you should be able to use that allotment how you see fit. But we're not talking about a specific amount of allocated data. The world "unlimited" only pertains to data consumed on your phone.