We arrived on September 5th. When we received our Magic Bands there was a sheet in the box that told us to put on our bands as soon as we left the house as we would need them for Magical Express.
I waited until we were walking down the hallway, past all the rental car desks, to get out our bands. When we got to the Magical Express area, I didn't have to pull out any paper work or anything. Just touch the band to the sensor and the CM welcomed us by name, told us the resort we were staying at and directed us to the correct line. Easy. That's when I started buying into the whole Magic Band concept right there.
Eric