As in the description, once 6 people are connected, a password is set on the server (a message is printed to chat saying so).
There's also a steamtools/connect plugin in there, but it is untested and so disabled (it's not even in the .smx when you click Get Plugin). To enable it you'll have to recompile with //#define USE_STEAMTOOLSCONNECT uncommented.
mvmautolock_version 1.2 - don't touch
mvm_password - Password to set once the server has 6 or more people. If unset, the plugin will not be enabled.
Previous plugin views -
August 20, 2012 (v1.2)
*Fixed a bug where a password would be set even if <6 players
August 16, 2012 (v1.1)
*Revised so that password is only removed if sv_password matches mvm_password
*If mvm_password is changed and sv_password is the same as mvm_password, sv_password is changed to match the new value as well.
August 16, 2012 (v1.0)