Clarification: They cannot force
existing owners into the flex program. Owners who bought conventional deeds still own conventional deeds with Staroptions (and Starpoints, if you bought from the developer.) And you will continue to use your deeded weeks as you always have.
You would only own "Flex" if you bought flex, or converted to flex.
This was announced some time ago - there are other resorts in this group, such as Westin Mission Hills.
Here is that thread:
https://www.tugbbs.com/forums/index.php?threads/new-westin-flex.266793/
The next logical question is: How will they get inventory for the Westin Flex Program?
-Vistana can buy units that are being sold on the open market.
-Vistana can convince owners to convert their timeshares to the Flex Program ($$$.)
-Vistana can keep units from developer sales, that go into foreclosure.
What they can't do: Force a deeded owner to convert to the Flex Program.