Man, that instant-on option of Chromebook is blazing fast, but imagine you’re using the device, close the lid, scurry on your way, and somebody else comes along, opens the lid and has access to all your goodies! You can trigger Chrome OS to require a password every time you close the lid in order for it to “wake up” again.
To do this, simply visit: chrome://settings/personal
There you go- safe, private and happy browsing!