I will test this out and let you know if it works Thank you.
Edit:
Well i was testing it out it does sort of work. It doesnt detect when a CT gets turned in a zombie so you can hear it trying to force weapon change to primary.
It is easily bypassed by quickly switching to your primary for a spilt second then back to knife.
also it doesnt affect players that were spawned as a terrorist and got transfered to the other team after zombie is chooses.