I have a silver '15 Limited and I have been constantly fighting off little rust spots with a clay bar then carnuba wax. Getting tired of it. my 1999 also silver did not have any rust on the tail gate when I traded it in. So I brought it to Szott Toyota in Waterford Michigan and the service manager said its not Toyota's fault/problem. It is the metalic dust from brake pads and discs sticking to the car and oxydizing on the paint. He flat out told me that it was not covered under warranty. He told me to clay it as I have been then put clear nail polish to seal it from moisture. Bull$4it! There is a pre-existing problem here. The rule of thumb is that the dealer will get less for a job if paid under warranty than if paid out of pocket so they will resist until you die. I will have to contact Toyota myself and start the process. Its only February and I am having to clean-off 4 spots just from this winter. It was completely free of rust spots in October. Has anyone else contacted Toyota directly?