Many buy over the phone, including sole resale buyers.
There’s actually no statement, T&Cs, caveat etc on the Tables in Wonderland site at all that it’s direct only, so this is totally unclear. In fact, now it’s quite the opposite, the old standalone website was removed and the new text was changed compared to before. The site now says show a ‘membership ID’ OR a card when buying it, and a ‘membership ID’ is the white card (when you are resale only you will see on your DVC site it says you can click to see your ‘membership ID’. This text changes if you ever buy direct, to say click here for ‘membership card’ and then it shows you a blue digital card instead.) So DVC themselves are only using the term ‘membership ID’ in relation to a white card.
So if it wasn’t open to resale, why would they say you can show something that only resale members have, to pick it up? You’ll also notice on that site there is now also nothing about it being direct members only. Here is the text:
“When purchasing in person, please be sure to bring the following:
Disney Vacation Club Members: A valid photo ID and your Disney Vacation Club Membership ID or Card”
I suspect if you try to buy in person, the CM will not be aware of what Disney’s own advertisement (website) says, nor will they be aware of what Membership ID actually means.
Not sure about US laws, but over here in U.K., to refuse to sell it to any member based on the website wording would probably result in issues for Disney, if for example, someone complained to the Advertising Standards Authority.