We are gonna use a script which checks if the player is nocliping. If so, it will tp him to the origin of the map (0, 0, 0). Just make a jail at those coordinates saying he's not a good boy!

First, you will need to download the script, put it in the right folder, setup hammer, and pack it in your map.

This will allow you to be sure the player cannot cheat by going through walls in your map with sv_cheats 1.

You can download the demo map on workshop to test the script here

Download the script: (remove space after "mega.nz")
mega.nz /#!QlcTxAaJ!DDVaRgg6b1cyNHb8q0UU8R3Q27HlQamdt1AZp1n3Rh0

You should have downloaded a file called stopnoclip.nut. Open it if you want to see details on how it works, the script is commented to help you understand.

Now, move this script in your csgo/scripts/vscripts folder.

Download the demo map as a .vmf: (remove space after "mega.nz")
mega.nz /#!QtESWLoK!XbrhEPbDtf3qSgw1RCitwS4EUBuTueatd_5BMTSMBM4

• In hammer, create a new logic_script entity. Open it's properties.
  
  
• Under Entity script, enter the script's path relative to the folder csgo/scripts/vscripts.
  (For example, it will be stopnoclip.nut if you simply put it in the vscript folder, and it will be utils/stopnoclip.nut if you put it in a folder named utils in the vscript folder)
  
  Or you can simply click on manage, "+", and select the script.
  
• Finally, under Script think function, enter Think.

See this guide on how to pack your vscript into your map

Remove space after "mega.nz" (steam is removing link otherwise)

-The script:
mega.nz /#!QlcTxAaJ!DDVaRgg6b1cyNHb8q0UU8R3Q27HlQamdt1AZp1n3Rh0
-The demo map (.vmf):
mega.nz /#!QtESWLoK!XbrhEPbDtf3qSgw1RCitwS4EUBuTueatd_5BMTSMBM4
-The demo map in workshop