Every match I have ever been to has had an announcement either vocally or in writing that the range is a cold range during the match, with the exception of the stage area. Carrying an unloaded mag in the gun will keep the dust out but so will a cover. They cost about 5 dollars for a cloth one or 59 cents for a bandana at Wal Mart. A mag in a gun, loaded or unloaded, gives the appearance of a loaded weapon. In my experiences with USPA matches (fairly limited) I have found that the people are easy to get along with and just nice in general. Simply asking the shooter not to carry an unloaded mag in his/her gun should be all that is necessary. WHY CAN'T WE ALL JUST GET ALONG????