The EAS code mentioned above has been used, on very rare occasion.
The only time I know of was in Huntsville, Ala., during the April 27, 2011 tornado outbreak, when a great deal of the community was without electric service due to severe damage to the TVA's power lines in north Alabama.
I would not expect the alert would be used for any of the COVID-19 shutdowns. Although it should be considered a proper use, I doubt most of those who own weather radios, have it programmed to alarm on this code, and thus few would hear it.