And yes, i have plans to remove my IT_AXE to make place for a new weapon, and the new "Axe" is called by my Impulse 13 now (look and feel from Call of Duty).
My Betty thing works the same way...
EDIT: i dont have tested your method atm but i think it wont work this way, because the "KnifeAttck" is in weapons.qc, and the botstuff comes after defs.qc and it will give a compile error (unknown value "KnifeAttck")