We explain to them at the beginning of the day that picking up paintballs off of the ground will cause the guns to jam either because they've picked up twigs, small stones etc with the paintballs, or because they've swollen up from the moisture on the ground. We will 'fix' this by emptying their entire hopper out (although we only really do this for repeat offenders).... on a seperate question, what do you guys do when you get a forager e.g. someone who doesn't want to buy more balls, so just picks them up from the field, i normally say that if they do it and the gun breaks, they'll be liable ...:
Matt.