You don’t need one if there’s an emergency, civil unrest would probably qualify as an emergency so non-licensed people can legally transmit.

The FCC hasn’t really punished anyone for not having a license other than those that are really bothersome/disruptive or are doing jamming. But like, if there’s civil unrest, the laws probably don’t matter anymore so you can just ignore the law.

But if you don’t have a license, you don’t have a callsign, and thus others will refuse to talk to you during non-emergency peacetime.