WiFi - does the device know when you are away from your home internet? Say I am at home, streaming a netflix video. It takes no data from my 2GB a month data play with Verizon, because I am using my internet from home (i believe). What if I walk 1 mile away, and try to stream. Will it automatically throw me on the 3G or 4G network, and start using my data from my 2GB? Does it know without me switching a setting?