Kasumi IS part of disciplinary committee while Shippou is part of the club management group
I believe the club management group also have permission to use CAD seeing as Juumonji was the leader of it prior to this.
But while they're not breaking the law with using their CAD, they will almost certainly get into trouble if they do duke it out.
They are allowed to use CAD, but if it is just to fight with each other then no, it's not okay. They need permission for duel like Shiba did last year.
Even everyday use of a CAD (outside clubs that is) probably would require some sort of excuse like to apprehend someone or to stop an accident.
Unless it's during the club recruitment time it's very strictly limited.
I wonder if the punishment will be suspension only...
(i forgor this part of ln, but I think it starts to come back now that I wrote this comment... I think it's gonna be fun next few chapters)