You should always assume that you might have to get by on what is in your pockets. This includes wilderness scenarios as well as urban - I had the fire alarm go while I was away from my desk recently - found myself in the street, no access to carpark, just what I walked out in. Luckliy I had phone, wallet etc, but the stuff stashed in my desk and car wasn't available to me. Happily it was a drill, but it is a reminder

By all means pack more, but be aware