Chemically speaking, rust is the product of iron, moisture and oxygen. Other factors can cause rust but none of them have any business around a gun, (acid, salt, sulfer dioxide and carbon dioxide).
Since the gun is made of steel. (iron alloy), and oxygen is present anywhere and everywhere, the remaining culprit has to be water, (moisture).
I would guess one of several possibilities exist. 1. air conditioning is producing excess moisture. 2 gun was subjected to water and never dried. 3 some form of acid was used to try to clean it. 4. gun was handled excessively and the oil/acid from someone's hands was left on the gun. Bottom line. I have serious doubts Kimbers rust any more or less than any other gun normally cared for. It should not have to be something you live with. Before you send it back, make sure it isn't the conditions you presented that caused the problem(s).