How do you feel about people walking through your campsite?

My brother-in-law's large seasonal lakeside site is a magnet for people taking a shortcut to the lake, even though the road is just one lot over. His two dogs are trained to poop where the traffic is heaviest. It doesn't take long for the beachgoers to learn the rules, especially the ones with bare feet. The "treasures" are picked up after the weekend. Problem solved.