The amount of people that don't know what you are suppose to do during a tornado is mind boggling...
If you grow up in Illinois or anywhere around the midwest, there's a high likelihood you've been through a tornado drill in your childhood.
Site safety plans typically include things about tornado warnings particularly in Illinois, where tornados are common. It's also common to have a site wide announcement system in case of fire or tornado warnings instructing people where to go and what to do.
Site safety plans typically exist to prevent lawsuits in the first place.