Waitlist

From what I've learned from talking to member services, the waitlist mechanism does not automatically book or hold rooms at the exact time that a cancellation occurs. Instead, at some unknown interval once each day, some code on their end goes across all the available nights for all the resorts at the same time and assigns available nights to waitlist requests. Therefore, there can be a period of time where nights that are waitlisted are shown as available since that mechanism hasn't done it's daily pass through to assign that night to a waitlist request.

That waitlist is not constantly scraping, it does it at certain times of the day (not sure how many, maybe only once) so that is why a room can come open. I have the best strategy when employing the waitlist is to also troll the DVC site at least once a day, especially in the morning to see if something has come open.