Walking is something that can work with 11-month reservations for rooms that actually have a real issue of booking full right at, or even before, 8 a.m. at 11 months out. Currently that consists of: AKV club level and value, BWV standard view studios (and resulting 2BRs which are all lock-offs at BWV) and to a much lesser extent BWV boardwalk view studios (and 2BRs), BLT standard view, CCV studios, Riviera Tower studios and to some extent standard studios, to a limited extent the VGF studios, OKW GVs in the near Hospitality House booking category, and Aulani standard view GVs and to a much lesser extent hotel rooms.
How it works, by example:
Assume you own BWV and want a stranded view studio for Oct 1-8, 2021, which is in the high DVC demand season. The 11-month date for making that reservation is November 1, 2020. But BWV standard studios often book full for October 1 within nanoseconds after the online reservation system opens at 8 a.m. eastern on Nov 1.
However, there are occasionally times for dates in Sep that the rooms are open beyond 8 a.m. so that you may, for example, easily be able to make a 7-night reservation for September 5-12 at 11 month out, so you reserve on Oct 5, 2020, the dates of Sep 5-12, 2021.
The effect of that reservation is to lock in your room for that one week and thereafter no one else who tries to reserve a standard studio with a start date from Sep 5 through Sep 11 can possibly get the room you already have for those dates or any dates thereafter. Then on Oct 11, 2020, you modify your Sep 5-12 reservation to one for Sep 11-18, 2021. On October 17, 2020, you change it to Sep 17 to 24, 2021. On Oct 23, 2020, you change it to Sep 23-30, 2021, on Oct 29, 2020, you change it to Sep 29-Oct 5, 2021. Finally on Nov 1, 2020, you change it to Oct 1-8, 2021. You have thus successfully walked the reservation to the time you want.
Though one might try doing something similar for the 7-month window, that always has a high risk of failure because all those future dates beyond the ones you initially reserve can, even if shown as open when you make the first reservation, easily disappear because the rooms can still be booked full by owners of the resort.
Its is obviously something that takes time to do. Moreover, even finding a start date for walking for some of those rooms can be very difficult, e.g., AKV club level studios (and as a result 2BRs) disappear right at 8 a.m. 11-months out, or even before 11-months out, for most days of the year and thus finding a date to start walking can itself be extremely difficult.