For the ultimate defensive walking stick, I see that Gandalf's staff, complete with "certificate of authenticity" is now available (made by United Cutlery and available from Knife Center, among others). It is only $129, so get several and save on shipping. Since it is adequate for Balrogs, goblins, and orcs in Middle Earth, it ought to be just fine for any emergencies today. It doesn't fold, and that is a minor inconvenience, but perhaps there will be a Gen 2.......