You can enable this feature while on your own server with "sv_cheats 1".

This feature has not yet been publicly announced.


Step 1: Make your own server (with bots)

Step 2: Open console and type "sv_cheats 1"

Step 3: Now type in console "give item_nvgs"

Step 4: Now just write "nightvision" in console
or
you can bind it with any key e.g "bind n nightvision"

Enjoy :D