UserAgent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36
Platform: 9000.91.0 (Official Build) stable-channel auron_paine

Steps to reproduce the problem:
N/A

What is the expected behavior?
No way to send emergency message not unless teachers are logged in to their email.

What went wrong?
We need an application/option that teachers/users will still be notified even they are not logged in to their Gmail. (Just logged in to their Chromebooks)

Did this work before? N/A 

Chrome version:   Channel: stable
OS Version: 56.0.2924.110
Flash Version: 

Defined by customer

Use case:
Due to the increase number of threats and as we are an international school,
we need an option in the Chromebooks to be able to stop our students from what they are doing
and display emergency message once there is a human threat.
For example the suspected terrorist attack in Stockholm

Motivation:
Windows servers are able to send a message across all logged in users, changing the color of the screen and blocking it for a few seconds with a message.
This is extremely important to be able to do as we have many embassy students.
If there's a threat to one of our 19 schools we need to be able to reach all teachers as quick as possible so they can lead children to safety.
I'm sure other organisations would be grateful for something similar