Here is a tip from one of my classes at AU.
Since we started using AutoCAD 2006 I've added this row to our acad.lsp that loads for all users. (setvar "BLOCKEDITLOCK" 1)
By setting the system variable BLOCKEDITLOCK to 1 you disallows opening of the Block Editor and editing of dynamic block definitions. In a multiuser company it can be useful if you have prepared a lot of dynamic blocks and don't want the users to mess with them.
From the help documentation about BLOCKEDITLOCK: Disallows opening of the Block Editor and editing of dynamic block definitions. When BLOCKEDITLOCK is set to 1, double-clicking a dynamic block in a drawing opens the Reference Edit dialog box. If the block contains attributes, double-clicking the block reference opens the Enhanced Attribute Editor 0 - Specifies that the Block Editor can be opened 1 - Specifies that the Block Editor cannot be opened