A heads up for you...this year in April, we did a short split stay, leaving AKL for WL. Entered MK with the "expired" key with no problem at the turnstiles, but upon going back in for EMH that evening (same "expired" key), we were almost told we could not come in! I unfortunately had left the keys for WL back at the resort and offered to go back, wanting the CM to understand that I was NOT trying to cheat my way in...she did finally say it was ok to enter.
Just glad we didn't have to go back to retrieve the correct key card!