We were in a cabin July 8-22 and there was a safe in the "closet" (really just a space with a closet rod). It was smaller than a piece of paper and about 3 inches deep. It works like other hotel safes - you lock it with a room key card and unlock it with the same card.
---Ritch
There is definitely a safe in the closet, but if it uses your room key, that is a change. I've stayed in the cabins about 10 times and I used the safe each time. The safe has always used a key that is in lock for the safe when you get there.