I agree with the earlier posts about cell phones and texting while driving. People don't realize how many are doing this coming at you on the highway. To me, that's much more of a concern than boondocking safety.
When returning from Az this spring, we stopped in a campground in Oregon miles from the highway. It was completely unlit and not a sole in it except for a camp host. Large overhanging trees and total darkness when we arrived made it seem like the spooky "Sleepy Hollow". After we parked for the night I looked out the window and saw a unit right behind us. I thought why the he** would anyone park so close and felt a little concerned. The next morning we awoke to discover the unit was a dumpster right across the road from us that we had not noticed when choosing our site. Made us laugh at how our imaginations do stupid things when it's dark.