Library returns

Today I took M and H to the library to return a movie and a book and also to get a movie and let M pick out a new book for the week. In the library there is a conveyor belt that you put your items to return on. M put both items on the conveyor belt and H felt a little left out but he was happy after I let him hold the new movie to check out. We got our items and were heading out the door--M was first and a bit ahead of H and I so I tried to hurry and catch up to her before she got to the street. I figured H would be right behind me but when I got through the first door I glanced back and saw H making a detour to the conveyor belt. I told M to stay and ran back but just as I was getting to H and our movie, H turned to me with a big grin on his face and was waving goodbye to the movie on it's way up the conveyor belt. What a happy little boy he was. I quickly informed one of the librarians that our movie we had just checked out was unintentionally returned this very moment. She was nice and went to get our movie but it had already been checked into the system again and was going to be sent to another person requesting it so she had to re-check it out for me and do whatever she did so the other person could get it again and all the while H is just happy that he got to put something on the belt and see it go up.