There are 3 stages of protection that I use.
Go onto any point entity such as 'light_environment' then turn off smart edit and press add.
Next make a Key with the name of 'no_decomp' and with a value of 1.
This is very easy to overcome but a clueless moron would never be able to get into the map!
The second level is to create a texture called 'locked' using vtfedit and any random picture.
Place this texture into your Garrysmod materials folder in a folder called tools. You may need to create the tools folder. Make a 1x1x1 brush with this texture.
This level is far harder to remove and for some reason stops the decompile process.
This final layer of protection is almost impossible to remove without a lot of knowledge on how bsp files are written.
It is very basic and easy to add and it greatly reduces the chances of your map being decompiled.
Download this file: http://www.bagthorpe...s/protector.zip and open it in hammer then copy and paste it into your map anywhere. Do not edit it in any way except its position. Make sure that it is not touching anything as well.
This is my method of protection and I know it works.
Hope to see some super secure maps soon!
Edited by Cyrill Jones, 02 October 2012 - 19:00.