I don't know what it is, but I get instantly frustrated when PAX sit in front on pickup? Don't have any idea why. Had some young buck sit up front today and started pushing all the dials on my GPS and radio. Immediately demanded he quit. I think most people know and are used to hoping in back so it's usually not an issue. I notice most the time it's the non US PAX's (Indian, middle eastern) that do it.