Why isn't there a Log Out Button in the Client?

I think there should be one, considering some people share computers, have multiple accounts, or just wanna hear the login screen music again :P Whatever the case, and though it may seem like a small thing to ask for, I've been wanting to be able to log out of my account and be returned to the login screen for a long time. Having to close the entire Patcher and reload it, is tedious sometimes.