Evidently, the "exposure incident" involved several kids dropped off in the Village by their team leader to hike up to the Hollywood Sign. Many had little or no water with them. The group was quite large - over 50 children from 12 to 16 years of age. When several began to collapse from exposure, all manner of resources were called upon to help.
You can get the full picture on the 4 o'clock news feed on many of the major networks as they are still in the Village along with police interviewing kids and the tour guide.
