I returned from my first Disney cruise last week. I did attend boat drill and they took the roll call electronically. A crew member had an iPod type device that had names and cabin number AND muster location. Pretty easy and fast way to do it...didn't take any time at all...she missed us initially so called out our cabin number, but I believe we were the only ones. She got the data from cards as they showed them or quietly asking as pax arrived...didn't make a big deal of it.