Well, we're still struggling to get our 19 year old to think about just in case and make smarter choices about what she carries on her daily college commute. As much as it feels like we're banging our heads against a wall, she did come home with a cool new find last week. She picked up a collapsable Vapur water bottle while looking for a birthday card at a Hallmark store of all places.
I've got no affinity with the company but you can find more details here:
http://vapur.us/products.php She likes it because it's light and takes up so little space. It's cleanable, attachable and freezable too. I like it because she's more likely to carry it with her!