People put way too much value on the EAS system as a means of communication.
https://www.theregister.com/2013/02/12/spoof_zombie_apocalypse_warning/
It used to be relayed via radio stations that TV stations monitored. I believe it comes via internet now.
I suppose all those means could be shut down by powering down. But the MSM would also lose their messaging system.
Adding: Stations, phone services, etc. have to cooperate. Legally.
OK, two lines. Everyone gets to vote. Accommodate. If accommodations are made for the blind, deaf, disabled, as they should be, then accommodate people who are asymptomatic- otherwise they would be in bed sick.
Turning away large segments of the population isn't going to look or sit well when they don't display symptoms other than a rigged fever.