I thought they went by the term combine... Regardless, if the rule to not kill them was in effect so they could build, they would not need superpowered weapons. Even easier, just take away their guns and give them an invincible playertype.
No such thing as an invincible playertype, and they don't have superpowered weps, they have a shotgun and a crowbar. I give them a crowbar because certain areas are accessed by a crowbar and the shotgun if someone decides they wanna start shooting them, they have protection so they can just not die and go heal somewhere else.
I even tell in big letters when you click the builder's button "DO NOT ABUSE THIS FOR KILLING" So sorry if some guy abused it and I didn't find out, but you know nothing about what I give them in their inventory as you have never clicked the button.