Once you've got a tribe, team, or cell, you're going to need to know how to identify friend from foe during missions, or when just sitting around a base camp.
I posted this over on LNL and it go way off course and off-topic.
Also, there is no way to do this before SHTF, unless you already have your group together. There is no way to tell friend from foe in WROL, but if I do see a guy has a Gadsden patch, I probably won't just shoot him outright.
Here is an article about choosing a symbol to wear all the time in SHTF with your tribe or cell. Some can even been seen at night, which carries another huge advantage and DISADVANTAGE, should your camp get attacked and you have security guys, running back into your base to fight off the attackers. You don't want to shoot your own guy in the fog of war as he is rushing back to help you defend the camp.
Also, if you choose something that can be seen by night vision, I would darn sure be certain my enemy did not have night vision or you are just painting yourself as one huge target.
Much more here at the link:
http://sipseystreetirregulars.blogspot.com/2010/09/praxis-iff-identification-friend-or-foe.html
Improvised white strips of cloth tied around an attacker's arm have been used for centuries to help soldiers identify friend from foe in night attacks.
Today's military of course have sophisticated Blue Force Tracker electronics to keep track of friendlies, but modern versions of "Mad Anthony's" hats with white paper in them can be found in the "cat's eyes" helmet cover band.
IR & UV cyalume sticks, with or without a holder, can be used at night and seen only by people with night vision devices. It would be a mistake in today's environment to believe that only your side has such devices.
But IFF can be even simpler. Beginning in the early 90s the Crips street gang wore British Knights shoes and took the "BK" logo to indicate "Blood Killer," in reference to the rival gang.
Shoes as identifiers remain popular today with the rival Mexican drug gangs. See this Texas Rangers' PDF analysis of a cartel vs. cartel vs Mexican Army shootout in Nuevo Laredo on 16 July 2010.
Go to Page Six for the photo:
"Many of the subjects appear to have the identical brand/model of shoes, or the same color schemes. This may be an indicator for friendly forces recognition, particularly during surveillance."
Figure it out, make up your own, and make sure that everyone in your tribe or cell has them. When the fog of war starts and SHTF, you'll be glad you didn't shoot someone who is on your side, and he/she will also equally be just as happy you didn't.
