Add this to your server.cfg
//IMPULSE 51 cheat
sk_dynamic_resupply_modifier 0
To show this works I went on my own server and typed Impulse 51 in console, I was immediately kicked from the server, and on checking the server log I get this message.
L 01/12/2018 - 09:10:13: "[B.n.B] Steve<196><[U:1:10983479]><Unassigned>" disconnected (reason "IMPULSE Cheat Violation")
The discusion