Mag customer service couldn't have been more helpful. Mag will give you name of a couple of warranty centers close to you. I had my choice of sending it to the Florida panhandle or Atlanta. I chose the panhandle. Called the center (more of a mom & pop electronics repair shop from the sound of it) and had a nice conversation.
They told me to send the light, charger, battery stick and bulbs. They said they would do a complete check of everything and replace any defective parts. For for the price of shipping to them I could have theoretically gotten a complete overhaul.
In my case it was just a switch. But remember Mag doesn't warranty battery sticks or bulbs. And I'm not sure how they handle corrosion issues. I imagine if it was a Mag battery stick they wouldn't give you a hard time.
I mailed light via USPS on a Saturday. Got light back via UPS on a Thursday. I would rate it as a 9.5/10.