Just because multiple kindle 3G models when completely stock (not hacked) have a social networking "feature" (or design flaw) that allows you to escape the amazon/wikipedia "3G walled garden" just by clicking links, it may be LEGAL (because amazon provided it by design, even if accidentally).
However, from a moral point of view, that "feature" should not be abused because amazon ATTEMPTED to restrict full internet access (when using the "experimental browser") for a reason (so that they could sell these kindles for less money with less "future internet access" preloaded into the selling price). Just because built-in social networking has fewer restrictions than the web browser is no reason to abuse it.
Please do not abuse things just because "you can", or we will all suffer from "
tragedy of the commons" in our kindle 3G service.
EDIT: However, that said, Jesse Vincent has documented this procedure for the Paperwhite in his blog, so just do as Nate the great said above and you will find what you seek. Please do not abuse it (i.e. emergency use only). Thanks.