It prevents other users to switch to your account without entering your password, while also keeps local copy of your profile without need to re-populate it from the scratch every time you switch to your user profile. Now, when you click on your profile name in the top right corner of Chrome, there's 'Lock' link showing next to your avatar. You need to 'Enable new profile management system' under chrome://flags/#enable-new-profile-management and restart Chrome.

Once there's a supervised account, you can sign out of ANY account set up in your Chrome.ĮARLIER, DOESNT WORK NOW: A sign out feature has been recently implemented, and works properly with Version 34 and later (locks profile asks for password unlocks with your Google Account password).

UPDATE (1): To be able to sign out an account, you need to set up at least one supervised account in Google Chrome (it can be even an account you never use).