Prized Possession or Librarian's Nightmare?

Yesterday morning I heard the boys doing some major brotherly negotiation before school.

Wesley: Fine. You can take it to school with you, but you have to be very careful with it.

Ryan: Okay, I will be,

Wesley: I mean it. Don't take it out on the playground at all.

Ryan: I won't. I promise.

Wesley: Okay. You can show it to Mrs. S. and if she wants to show the class that's fine, but that's all. Got it?

Ryan: Got it.

I couldn't for the life of me figure out what they were talking about. What would Wesley treasure so much that Ryan practically had to sign over his first born child to take to school?

It was this:

Ryan's class had a field trip to the conservatory yesterday and this book has a wonderful section on butterflies in it.  Great. I can understand why Ryan wanted to share it, but I don't understand the blood oath to take good care of it. I mean, LOOK at it. From that picture alone you can tell the binding is broken.

See! But you'd better be careful with it

Wouldn't want it to get dirty or anything, right?

Think he'd notice if I brought home my "discard" stamp from work and made this book disappear?