I love the outdoors, but I'm not really an experienced outdoorsman, hiker or camper. I have little to no education in outdoor etiquette, beyond the really obvious stuff (pick up your trash, etc.).
Last week I took my family on a road trip through a mountainous area, and we stopped at several little mountain streams and waterfalls to explore the area and enjoy the view. On many of these trails, my young toddler had a great time picking up dozens of pebbles and small stones from the path and throwing them into the stream / waterfall / pond / etc.
Only later I thought to wonder if there's something wrong with doing that. Were we contributing to erosion, disturbing animal habitats, interfering with water courses, or something? Should I stop him from throwing rocks in the future and educate him about why that's not environmentally conscious, or is it not a problem, so I can let him throw pebbles to his heart's content?
(My personal guess is that driving our car through the area [on public roads] probably did more environmental damage overall than throwing a few pebbles, but, well, I really don't have any education to back that up!)