Haven't seen it in-person yet, but I'd presume it's as quick as a Photopass photographer scanning a Band or RFID card. Push button, scan ticket, scan Band to associate with that ticket. If the ticket is linked to a MDE profile, the system would automatically do the necessary linking. CM doesn't have to do more than that.
Someone posted in another thread that the CM can also sell a Band and set it as "hold for later linking" which allows the Guest to link it to a MDE profile themselves. (Which if you think about it makes sense. Otherwise why would there by an option on the MDE site and app to link a Magic Band by serial number if there wasn't a way to obtain an unlinked Band?)
-Rob