We have been very fortunate but we have also, by and large, had teenagers that were adult in their attitudes. Horseplay and daredevil acts simply are not acceptable 20 miles from the nearest car. Some adults are often more prone to injury than teenagers because of attitude. Even if you didn't pack it in - leave it better for the next guy. Anything that doesn't burn must be carried out - not buried.
Aluminum lasts forever and foil in campfires is the most common sin of backpackers.
Try to always get water from springs and avoid the large streams. Above 10,000 feet elevation we will drink water straight from small streams coming off mountains with no trail crossings. It is safe to assume that anyone up there will not be the type to foul up a water source. Below 10,000-feet we purify or filter any surface water. We have taken 50 different people into the Weminuche over a 15-year period and never had a case Giardia or other stomache problems following these guidelines.