Login on waking from sleep, but not screensaver / sleep display

Question

Hi all, been trying to get rid of the login from screen saver / sleep display, while keeping the login on waking the computer from sleep. The reason I want to do this is because I frequently use a Hot Corner to sleep the display while listening to music etc, and having to enter a password just to change tracks etc is a pain But obviously I want to keep the password protection when the computer is put to sleep, as it always is when left unattended.
Anyway, based on initial Googling, I first tackled the problem by installing SleepWatcher from http://www.bernhard-baehr.de/, and adding this line to the global /etc/rc.wake script:
/System/Library/CoreServices/Menu\ Extras/User.menu/Contents/Resources/CGSession -suspend
However, this wasn't very satisfactory, because after waking the computer up from sleep, you initially get a normal session, which then suspends after 3 or 4 seconds. During this time you can interact with the session as normal and move windows etc, so it kind of gives you the impression that you don't have to log in, and then you do, so it's a bit clunky, and also doesn't feel very secure.
I thought I managed to improve the situation by moving the 'suspend' command to SleepWatcher's /etc/rc.sleep script instead of the /etc/rc.wake script - meaning that your session is suspended just before sleep, so it's already suspended when you wake the computer up. But then I noticed an even worse problem - my "Sleep Display" Hot Corner stopped working after SleepWatcher suspended my session!
Yes that's right, every time the 'suspend' command ran in conjunction with SleepWatcher, my "Sleep Display" Hot Corner got disabled, and didn't get re-enabled until I completely logged out and back in (or rebooted). So I stopped using SleepWatcher, by removing the 'suspend' command from any SleepWatcher scripts, and now Hot Corners work as normal again following successive sleeps.
So next I thought, maybe I could write an AppleScript that toggles the "Require password..." checkbox in System Preferences, perhaps to use in conjunction with SleepWatcher, so that the checkbox is disabled when the display is put to sleep, and enabled when the computer is put to sleep. I actually got as far as writing an AppleScript that toggled the checkbox, and was about to attempt to integrate it with SleepWatcher...
...then I stumbled across an old thread, where they talk about updating plists under com.apple.screensaver, in order to solve a slightly different problem:
http://forums.macosxhints.com/showthread.php?t=14085
Despite the thread being a few years old and trying to solve a different problem, the following command sounded hopeful so I thought I'd try it:
defaults -currentHost write com.apple.screensaver askForPassword -int 0
...and lo and behold, it works!
My mac is now behaving exactly as I want it - prompting for password on wake from sleep in the normal way as it did before, and not prompting when I merely wake the display (or screensaver)!
This is in conjunction with having the "Require password to wake this computer from sleep or screen saver" checkbox turned ON in System Preferences.
But the puzzling thing is, why does it work? Is it safe? Are there any side-effects and am I likely to need to re-enable it following software updates? Does it work for anyone else?
When I query the values under com.apple.screensaver, I get the following... I have no way of telling what the askForPassword value was before I changed it:
$ defaults -currentHost read com.apple.screensaver
askForPassword = 0;
idleTime = 0;
moduleName = Flurry;
modulePath = "/System/Library/Screen Savers/Flurry.saver";
tokenRemovalAction = 0;
Basically I'm very surprised that a simple one-line command seems to solve the problem, when there are so many threads where people have asked the same question, and either been told it's not possible, or told you need to do weird stuff with SleepWatcher and/or Applescript, which is often incompletely explained, more complex and less effective.
So, is the one-line askForPassword solution too good to be true?

Answer 1

Thanks. I think for an office-type environment, it is an unusual requirement.
But let's not forget, more and more people use their computers in living-room type environments, for tasks such as playing music or watching films on a remote display. You're typically in a much darker ambience, which you don't want that to be shattered by the bright, white glare of a computer screen all the time!
So you need total control over whether the display is on or off. This has nothing to do with leaving the computer unattended. You're still there, "using" the computer, you're just not necessarily using the display.
Anyway... you are right, I toggled the "Require password..." setting in System Preferences off and then on again, and the "askForPassword" plist value changed itself to 1.
However... the behaviour of my mac has not changed. It behaves the way I want it (prompt for password on waking the compuer, but not on waking only the display), regardless whether the value of askForPassword is 0 or 1.
Even after rebooting.
Strange... what have I done?