One word - bullshit!
I'll bet a million bucks that by the end of the year when all the "fools" have switched over and are beyond the return period, locked into their contracts, Verizon will announce that the all-you-can-eat broadband buffet is over, just like Virgin Mobile did last month. There is nothing to stop them from doing so.
Seriously, carriers either are able to support an uncapped plan, or they shouldn’t even offer it. Announcing that you will just to screw your customers a few months later is typical of today’s lousy US carriers obsessed with getting a fast buck at whatever cost. You can be a company that makes it’s money with scams, or you can recognize that there is a demand for fast, uncapped broadband, and own that market by offering heavy users what they want.