I have never been to an event yet but will be at
MNSSHP this year. With people dressing up and so many people walking around isn't even spotting a wristband hard? as it could be on either wrist or could end up hiding under a costume?
Since there is checkpoints, rides, and meet/greets wouldn't all those CMS be able to get pretty much everyone who isn't supposed to be there?
Not sure exactly how the magic band stuff works for RFID but with enough R/D which Disney has had plenty of they could easily pinpoint the direction and aprox distance to the MB that didn't have the ticket tied to it. People could opt in to the old school bands if they didn't have a MB.
Who knows though maybe Disney's system isn't to that level yet but I can only imagine in the future the cost it would cut from having to hand out the million or so plastic bands over the countless parties they have all year right?