It's easy for a high-volume institution with many student workers at many desks to mistakenly check a book out to a user that is not for the user in front of them. Because the TN# is attached to the user, ILLiad then indicates that the item is checked out to the requesting user when the book may have been given to the wrong user. A simple pop-up during the checkout process confirming the username/ID# of the user the item is being checked out to would help prevent this. (and the ability to undo if necessary)