Yes, I have had last minute luck. I've picked up ADRs I had been trying to make for months a day or 2 before. The main thing is to be persistent. Try online multiple times a day. The more you try the better your chance of picking up a cancellation before someone else does. Now with the cancellation policy, I don't know that your chances the day before are very good, but someone might change their plans 2 days before. We discovered our first trip to WDW that the pre-park opening breakfast was a disaster for us, because DD is not a morning person and with the one hour time change getting to the parks by rope drop was hard enough. As a result, I cancelled a prime pre-park opening Tusker House ADR the day before- now it would probably be 2 days before, but it can happen. I'm sure someone was thrilled to pick up my cancelled ADR.