Concerning the legality of using vision unlimited with a ppc: A clerk at a Sprint store was aware of the issues but very tight lipped. No matter how hard I tried to press him on the issue, he wouldn't commit - which is easy to understand.
What I thought he was hinting at is that if you abuse the service, sprint may start charging you for mb of data. What does he mean by abuse? He wouldn't say. He also couldn't give me any idea as to when Sprint would settle the issue.
I think I would probably fall under the category of an abuser. For this reason I'm hesitant about signing up for a year and then getting wacked after a month or two.
Obviously Sprint is weighing the matter. If they ever consider a BT phone, the issue is unavoidable.