My family will be travelling to Florida nest month. I'm only going to add easyroam to one of our iPhones, mainly for calling back home, and for GPS using Google Maps when we are driving to and from the airport. Most places that we will be, have WiFi. Will easyroam kick in if I send a text while on WiFi? Does it matter if it's imessage or regular texts? I don't want to be paying $7 a day to send a few texts, on days I don't need the cellular network.