When you use your arm band there is definitely information that comes up for the cast member. I'm not sure how much information and if it comes up every single place, but I know for sure at least at the hotels it does. Me and my wife took a trip to Epcot a couple of weeks ago for the Flower festival. When I would re-enter the hotel parking area at night after being away for the day, I had to roll down my window and they had to swipe my arm band. One night I accidentally wore my wife's armband instead of my own and the guy at the gate said "Thank you ***" and then he had a weird look on his face, realizing he had just called me a woman's name. And then he started making jokes about maybe I need to shave and maybe add a little eyeliner. It was one of the highlights from our last trip.
Also, they use the armband for EVERYTHING. Entering the parks, entering the fastpass lines, etc. etc. And more than once they would call me by my name.