Anonymous
The grey man is the person who look around and blend in with whatever the environment is. The one able to change when needed. The one able to pass for what he is not.
Today it might mean not having political stickers on your truck. Or open carry even if it is legal, unless it is common around you. Or walk into a liberal area are with a MAGA hat or in a conservative one with a “I’m with her” shirt.
In a SHTF situation, being the gray man might be joining the FEMA food line even if you have plenty at home. Loose some weight so you don’t look like the fat piggy among the runts. Loot a store even if you don’t need too. Wear run down or not very clean clothes. Wear a normal coat rather than you cammo and hide the AR under it.
I guess what you need to do depends on the situation and your understanding of it.