As we had no particular reason to go back to the convention other than to see if any of our door-prize tickets were drawn, I set the alarm for relatively late. However, check-out time here is 11 AM, so I need to get cracking.
Incidentally Sea-Pac uses the same style of badges every year -- a cardboard cut-out that fits into a clear plastic pin-back holder. They encourage people to leave the holders behind in boxes provided for this purpose, to save Sea-Pac money. They can get away with this because admission is only $10, so there's no margin in counterfeiting badges. If it cost $200 to get in the door, I expect you'd see lots of fake badges.