A breached alert platform can do more damage than a fake message. It can borrow the authority of an emergency system and force attention across a whole country, so the immediate risk is public alarm and lost trust in a life-safety channel.
Brazil’s national Civil Defence system was used to push fake Extreme Alerts to phones in at least five states, including São Paulo, Rio de Janeiro, and the Federal District. Nine of the ten messages went out through Cell Broadcast, which overrides silent mode, and officials took the platform offline after the compromise.
The more serious risk is what this means for the next real warning. If an attacker can speak through an official alert channel, people may doubt the next flood or landslide notice even when it is genuine.