Special Keycard over Preempts

When partner opens any Preempt from 2D thru 3S (except 3C) we play that 4C is Special Keycard When Partner preempts 3C we play 4C as extending the Preempt and 4D as Special Keycard

Responses to Special Keycard are:

Special Keycard is on over Interference so long as it is a jump. If we cannot jump then 4NT becomes Special Keycard.