Seriously. If you’re in a school, church, community center, hospital, or wherever, do it. It will create chaos as the building is evacuated. It will disrupt the operation as the volume of the alarm will interfere with communication by ICE agents. It will force a response by the fire department and local law enforcement.
Yes, it’s illegal. Civil disobedience is illegal by definition.
Spread this far and wide on social media, especially if you and or your friends/family/colleagues work in such institutions.