Here's my situation--1 smartphone (mine) on 3G and 2 dumbphones. All were activated at the same time, contract is up in December. Shared family plan on voice, unlimited text, and I have unlimited data.
If I upgrade to a Maxx HD on one of the dumbphone lines and then do the phone number/line switch, I get to keep unlimited data. I then give my Droid 2 to my son, who would want to have data access--how will Verizon bill me for that data usage on the Droid 2 phone? It's 3G access. Assume the third line remains a dumbphone line.