Brian,
I would include that the two most common causes of injuries and fatalities are water and falling injuries do to "easy" climbing.

I have a very poor sense of direction and can easily get lost in WalMart. One thing I do at a trail intersection is make a very small cairn (3 golfball size rocks) 10 feet before the intersection on what would be the left side of the trail when I come back. I put it where it can't be seen from the trail and remove it when I come back.

Except for tourist trails I carry enough gear to spend a couple nights out, even on a day hike. It's not unusual to hike a whole day here without seeing anyone.

I've never seen a person with a map decide where they should be based on time before figuring out where they are. I've also never seen a person take a bearing at a trailhead to see if they are starting on the right trail.

In NOLS wilderness navigation (I think) they recommend identifying your position in 5 (I think) different ways.

The leader should call the controllng agency before going on the trip to see if there are any problems with the trail. Last year, we had a lot of blowdowns and many trails were impassible. The year before I found a trail was closed due to a plane crash at the trailhead that started a forest fire.

Loop trails aren't a good idea because you can't let a person with a blister wait for you to come back the same direction. Never leave an inexperienced hiker alone to wait for the group to come back.

Don't go on a trail that starts out downhill. It takes at least twice as long to come back up the hill. There aren't many of these, so they are easy to avoid.

Ask permission before putting anyone's picture on YouTube or a Meetup site.

That's all I could think of. I hope you get one idea from it.