Just an FYI. The Sheraton Miramar Vina del Mar, Chile told me they had a 3 day maximum too. It is possible that there was some misunderstanding and language issues - my Spanish is not great and we were conversing in English.

I was there on a 5 night point stay, which might have been part of the reason-- or not. My stay there was fabulous and I have no complaints, so I am just adding a data point here. Perhaps what they really meant was that I had to have the room cleaned on the 4th night and the 5th night was my last, so 3 would have been all I could have earned anyway. Or maybe they meant what they said and 3 MAGC vouchers per stay really is their limit.