set askforpassworddelay in terminal using defaults

AFAICT, the default setting for that item when initially setting the Security prefPane to require a password is 0.0, all I can suggest is to delete the plist and reset it. BTW, that plist is unique to each user. Here's mine:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>askForPassword</key>
<integer>1</integer>
<key>askForPasswordDelay</key>
<real>0.0</real>
</dict>
</plist>

See http://developer.apple.com/library/ios/#documentation/Cocoa/Conceptual/PropertyL ists/Introduction/Introduction.html for more details.

AFAICT, one user's setting shouldn't affect any other user's setting. Maybe I'm missing the point.

That's confusing, but then on my single-user machine, I don't deal with multiple users or locked screensavers. Download the appropriate guide from Mac OS X Security Configuration Guides
and peruse the sections on +Securing Desktop & Screen Saver Preferences+ and +Securing Security Preferences+.

What worked?

OK. Thanks for the feedback. Good computing.