Oh ugh, that sucks! I just switched pocketbooks to one that zippers closed. I make sure whenever I leave anywhere I zip it shut. Its a lot harder for someone to reach in and take if they have to unzipper it.
I'm so sorry this happened to your daughter.
It could happen to anyone really... but it's really a hassle. It always seems that the person who was violated not only suffers the loss/violation but also has to deal with the mess and financial aspect of the clean up.