i think all they need to do is incorporate a photo. events such as cannes require you upload a photo when registering. the badge you receive is like a drivers license. they have security at all entrances who just check to make sure the picture matches the person.
including a photo might be the next step, but the only problem i see is it would really slow down the process of letting everybody into the convention center.
this year im curious how well the whole RFID process will slow things down. especially when 1st using your badge at the convention center, because if it doesnt work you can't get into the convention center and will have to go to customer service.