A link to the NOLS press release here.

I've hiked some in the Chugach National Forest in SW Alaska. Our tactic was to constantly make noise just on the off chance we would come across a bear. The real problem may be that since the bears don't make noise you can get surprised. We were walking a well used trail when, with no warning at all, a very large dog ran up on us. He was friendly so no problem, but we never heard him coming. I doubt we would have heard a bear and in some of terrain we wouldn't have seen one either.

National Park trail and ADFG crews (fish & game), on which my DD has worked, always have a member whose job it is to provide protection against bears. She ends up carrying the 12 guage most of the time. The NPS does provide firearms training to all crew members before allowing them out on the trails.

DD's said that the crews worry more about black bears than grizzlies, but that may be because of her location in SW Alaska (Prince William Sound).

Sounds like all the kids will survive which is great news. And, NOLS did provide them with a PLB, which they used. It would be interesting to read the first person accounts of what happened.