Ability to control or mute the volume from the login screen

For those that enter meetings with their laptops running Ubuntu, it's easy to forget to mute the volume before leaving the house. If running late to the meeting, it's distracting to hear the Ubuntu login sounds as someone speaks. If there was an option to mute or reduce the volume before logging in, that would greatly aid these people; should not assume that Fn controls work/exist on the laptop to reduce volume.