MediaShout has a feature called Lock The Song Library which will lock the song database so that no changes can be made to the main library of songs.  Here are instructions for locking the song database:

1. In MediaShout, go to Tools>Settings>Songs.  (Tools>Settings>Text in v3.x)
2. Look for Options on the right.  (Look for Lock The Song Library on the left in v3.x)
   
3. Check the box that says Lock The Song Library.
4. Apply the setting and close.
   

NOTE:  With this feature enabled you will not be able to add songs from scratch.  You need to unlock the song library to be able to do this.