After deciding my kids needed some minimal emergency "stuff" with them when they are at school or on their way to or from same, I found out it was a lot harder than I thought to equip them for several reasons:
1) If I get them really good quality stuff, with the high probability that it will be lost or loaned in short order, I will be reluctant to replace it right away like a good preparedness nut should.
2) If I get them junk, it may not work when they need it the most and I'm not there to help them.
3) Schools are getting almost as bad as airports with what they will and won't let kids keep in their backpacks.
4) Wearing a whistle around your neck is not "cool." It is very, very, very important to be perceived as "cool" when you are in school, so the emergency stuff has to be out of sight.
So - I compromised. Went to Lowe's Home Improvement and bought two plastic snap hooks with attached split rings and two Eveready disposable squeeze lights, no. SL240BP. Also placed an order for two Acme Tornado whistles from Ranger Rick's, because they glow in the dark and are therefor "cool."
Total cost - $5.50 for each unit, and they will be clipped to an inside key ring loop in each backpack, out of sight but available for instant use.
Still, I was yearning for Photon IIs and Fox 40s!