When I set out to cross the country by thumb earlier this year, almost everyone I know was convinced that harm would find me out there on the road. One dear friend followed up on every post before I left by pleading with me not to go. He was certain that I would be assaulted, probably killed, maybe dismembered. So pervasive is our fear of the unknown. What, you may wonder, does this have to do with holiday shopping? Lately I’ve been bombarded with ads for a device that promises to assist me in escaping from a car before it sinks in a pond (this scenario presumes I have recently…