In any crisis, where you have to rely on what is in your BOB, to sustain yourself, family, or friend's, you can NOT risk having your bag taken away by the police. In a urban crisis, you MUST still obey the laws that have always been in place. Dont fool yourself that you can just do what ever you want, because you CANT.
Even today, homeless people have thier packs taken away when they are breaking even the simplest of laws, like sleeping in a public park.
You can not affored to lose your only means of survivle. Obey the laws, keep to yourself, dont make a scene, and just blend in the best you can. And NEVER EVER tell anyone what is in your bag! You dont want to bring any attention to yourself from the police or the public.