True that !
'Grey man' includes that manner in which you carry yourself (posture),
your choice of clothing and clothing color,
and includes selection of shoes, hat, gloves, and backpack.
If people are wearing sneakers, you don't travel the city with Timberline boots, or sparklie new Nike's.
If youthful gangs rule that area, you are familiar with their 'colors', and how and where they wear them.
You imitate like a chameleon, and look like you belong there.
You blend in .. and are quickly overlooked and forgotten - you become 'grey'.