I think it's still too early for "last minute" cancellations considering we have no schedule. Personally, I have a couple of ADRs I'm holding onto since our plans aren't final yet, so I'd keep checking if I were you. There are also services you can pay for (some which cannot be mentioned on the DIS so you'll have to Google) that will ping Disney's system and alert you when a desired ADR comes available. We used one of these to get a BOG ADR in December on a party night. I want to say I got notices of 10 cancellations in the month that I had a notification set up. I think I want a H&V ADR on June 5th, so I'll check the ADR cancellation thread for awhile, but once we get to 50 days out or so, I'll sign up for the ADR service. With BOG, there were a whole bunch of cancellations between about 60 and 30 days, and then nothing. With these SWW meals, I think we'll see more ADR cancellations when the schedule becomes available.