Explanation for rule #20

Explanation: See that pile of paintballs lying on the ground there? Look tempting don't they? Well there's a reason why they're still there, the second a paintball hits the ground it starts soaking up moisture. The ground's not wet you say? What about those little bitty pebbles and pieces of dirt? Even a little grain of sand has the potential to scratch up your barrel and turn it into a paintball shredding machine. We don't like it when the rental guns turn into Wagner power painters either.