I would add communications to this list. A cop by himself is just another armed guy with some - possibly inadequate - training and experience. What makes law enforcement formidable is the fact that they can summon a hundred other armed guys on short notice. A cell phone, ham radio, or CB is indispensable in a crisis situation, especially for untrained non-LEO civilians caught in a bad spot. Even most people who "pack" have limited ammo. Not so much a problem these days with most people carrying cell phones, but knowing who to call (911 calls from cell phones can get routed to the wrong jurisdiction or even state, for example)and how to report pertinent info is not something most people have to worry about.