5.6Criminal Activities

Gangs — Civilian Clothing

A gang member in civvies is a civilian. No joining gang fights, no shooting, no robbing — with one ambush exception.

Out of uniform = civilian. A gang member in civilian clothing is treated as a civilian. They cannot join in on a gang fight, cannot shoot, and cannot be shot at as part of the gang-on-gang exchange. Engaging while out of uniform breaks both this rule and the kill-or-rob exception above (5.5).
Ambush exception: if your gang is the one being ambushed, members who happened to be caught out of uniform at that moment (mid-change, just arriving, etc.) are not penalised for defending themselves. They are still treated as civilians for any kill+rob exception, but reasonable self-defence is allowed.