There's kind of an old saying about the best way to get away with something is to look like you belong there. I work in the construction industry and have to occasionally go to job sites to check layouts or measure as-built diminsions. I carry an orange safety vest and a hard hat for those times. An orange safety vest and hard hat is the "uniform" for construction workers, highway workers, and all of the public utilities from water/wastewater to subway maintenance. You'd be amazed at the places you can walk into without a second glance or question.

In a SHTF situation you could probably walk out of areas that are being shut down just because you look like you have a job to look like you're there to help fix the situation.