Sorry Coz:tinysmile_twink_t2: but my observation is the foot soldiers are a lot cleaner in the back country than the Cavalry. I think it has more to do with the riders having time for snacks while the horse does the work and wrappers get accidentally dropped and it's too much hastle to stop, get off and pick it up.
My next observation is boy scouts can be messy. But don't blame the boys, it's the leaders that are failing in the teach and the follow up. Recently, three of us Webelos leaders had a combined group hike. The boys from one of the groups was constantly dropping wrappers and the boys from the other two groups was constantly catching them at it. They had no idea what LNT meant and showed it when we hit the switch backs and straight over the edge they went. As my boys and the other dens boys kept critiqueing them, it was obvious the leader had no idea what it was all about.