The game doesn’t give you any way to enforce this. Howerever, it would be very easy to require everyone to submit demos, and have any clan who use the wrong number forfeit. The only problem then would be finding clans who wanted to play in such a system.
Mind you, I think the idea is silly. It only takes a few shots to gib, and panzerfausts, grenades, rifle grenades and support fire all can kill and gib instantly.