Ambiguous Emergency Alerts

Why do we get ambiguous Emergency alerts?  You would think that if there were truly some emergency, the emergency would at least be described so the people seeing the alert would be able to decide about some important action they should take. 

Emergency Alerts with absolutely no information on the nature of the emergency other than the time frame and the geographical area pretty much condition people to just get up and make a sandwich or make that trip to the garbage can to take out the garbage rather than just sit there watching an emergency alert about nothing in particular.

If it's a test, say it's a test!  If it's not, say why the alert is being broadcast.