Yes, there was one of these switches installed with my SMB penthouse install last November. The purpose, obviously, is to keep the lights (pressure activated) from being turned on when the top comes down. The kill switch, for lack of a better term, is located on the passenger side under the upholstery in the middle of the van, directly under the penthouse lift arms which will apply pressure when the top comes down. I believe you can feel a slight bump there when the top is up and can even activate it by pressing down with your finger.
2012 E350 RB XLT Wagon, Agile 4x4, SMB penthouse