All versions prior to 4.0.0 will no longer work

Lockdown will allow you to see who in your guild is saved to what instances and raids, as long as they also have Lockdown installed. This should save a lot of time of people asking who is saved to what.

You can view lockouts organized by Character, Instance, or view the lockouts of your other toons.
An asterisk (*) signifies that you are saved to the same raid ID.
*Keep in mind if a lockout reset has occurred and you have not logged in with a character yet their lockouts will be out of date*

Slash commands:
/ld works anywhere you can use /lockdown. If you know of any other addons using this slash command please leave a comment. /lockdown - Opens the GUI showing the saves of your guildies who also have the addon and your other toons
/lockdown mmhide and /lockdown mmshow - hide and show the minimap button
/lockdown refresh - refreshes and sends out your own save data and requests the save data of others online.
/lockdown toggle - toggle the Lockdown window.
/lockdown wipe - Wipes the database and then repopulates your own saves into it. Also requests saves of anyone online with the addon.
/lockdown ver - shows your version and the version of others with whom you can communicate

Thanks to ddumont whose library lib-ScrollingTable saved me much time.
I'm also using the Ace3 AceTimer library.

Current issues:

Plans for version 4.0.1:

Future possibilities:
Track how new database is
Share other users saves with guild.
While in group see other group members' saves
Localizations?