I fell asleep last night with the laptop on battery power and the clamshell open. When I woke up, the machine was asleep (screen off, battery status after waking - 94% - indicates it was sleeping all night) but pressing a key woke up the machine and took me straight to the desktop instead of prompting for a password! I have been having other power management problems with Mavericks such as it ignoring the timeouts for the screensaver, screen off, and sleep that I had set, but those were minor annoyances. If the machine no longer reliably prompts for a password after sleeping that is an enormous security hole on a portable machine. This is making me consider going back to 10.8 as I simply cannot trust that my machine will be secure when I close the clamshell or leave it unattended (goes to sleep). Has anyone else had this problem?