Just tossing in my experience this week (now that it's FINALLY over)....
I was hoping to snag a little under 2 weeks at the Poly, half standard/half lagoon view. I had to change the order of my split a few days prior because of the availability I was noticing (first day of lagoon was already gone, but standard was available).
On my 7 month mark, standard 1st day was unavailable. The next day I was able to get day 2/3/4 in between unavailable spots. I ended up grabbing day 1 as well before my wait list came through and cancelled the waitlist. (this was a Sunday/Mon/Tues/Wednesday). Since then I've just been watching to see if my next few days opens up to call and add on. It hasn't. They've actually slowly booked up. It's pretty clear people are walking their reservations since it's just going down the line booking up.
Yesterday I was ready to book second half of my stay and was glad that I finally could since the first day hadn't been booked up. Sadly, the website was down the entire first hour and when I called at 9a I didn't have my member number so the CM wouldn't help me. I found it, called back 2 minutes later and there was already a 15 minute wait. Of course, now my first day was booked up for both standard and lagoon (I would have just extended my standard portion at this point. I don't even care anymore). Super annoying! I've never had to have my member number before, and I didn't have it readily available because the website was down!
Anyway, today I was up, the website was working, and I had a full Saturday-Friday opening for both standard and lagoon view. I had my screen open to the booking page ready to go, and right at 8a I was able to book the full Sat-Fri in a lagoon view room. So, thank goodness, it's basically over. I'm still missing those 2 nights from earlier in the week but I've got them wait listed and since they're a Thursday/Friday I'm hoping that they'll open at some point. I'll keep checking. If not, I'll probably just book those two nights somewhere else, although it's going to be a pain in the butt to switch.
Anyway, moral of the story - if everything is working as it should be and you're ready to go with the mouse button with all your info filled out right at 8a, you should be okay. By the time I went back to check availability after booking, lagoon was booked for that first day again and standard was available. Checked again about 5 minutes later and standard was booked for the first day. It definitely goes quick. I wish I would have just walked my own reservation to be honest. I ended up booking an extra day just in case we wanted to stay a little longer. I'll be darned if I deal with this again! lmao