I was on a WN flight LGA-BNA last year that was the 1st flight of the day. The MDW flight scheduled to depart our gate before us was delayed for a MX issue. WN ended up giving my flight's plane to the MDW flight. My flight was cancelled.

No interlining whatsoever. I had to be in BNA that day. No choice. I called AA and all nonstops were full. WN's only option to get me to BNA that day was to fly immediately from LGA to Canton, Ohio then on to DCA then finally to BNA. I was with about 30 other pax from the original flight. I missed an entire day of business meetings because I arrived almost 10 hours late.

So WN isn't much better in this situation.