One thing people forget is that emergencies happen in degrees. It doesn't go from everything's honkey dorey to mad max in 5 minutes. So while technology might be offline, you can still use cash. Keep a couple hundred bucks stashed in your bag, that'll get you a hotel room when credit card verification is down. Or food from a restaurant, etc. It'll take a while of things being really bad before people with normal resources start realizing they want silver.