A checkbox in gdm login to mute sound before you login

When you are in a location, where you shouldn´t be noisy (like a library) and you start your Ubuntu Notbook, it is always a fast pressing of the notebooks special function buttons to mute sound, sometimes it works, sometimes it doesn´t.
So it would be great if there was a small checkbox for "silent start" or similar. I no, that at that point it wouldn´t avoid the "drumsound" of gdm-login, but the usual login sound.