Daughter left earbuds in open desk and they were stolen. How should I teach personal responsibility without victim blaming?

My 9 year old daughters school had a book fair this week, and I gave her $10 to spend. She bought earbuds with it, and left them in her desk for gym class. Another class had a lesson in her homeroom, and when my daughter returned from gym, the earbuds were missing.She's been very bothered by this, and I've talked to the school, but nobody saw anything so there's nothing they can really do. I'm trying to help her understand that she's responsible for making sure her stuff is safe so something like this doesn't happen again, without making it seem like I'm blaming her for them getting stolen, but I'm drawing a blank. Does anyone have any advice on how to handle this? via /r/Parenting http://ift.tt/2dor7RF