I would be really surprised if this is actually implemented, since they are essentially taking away a benefit of ownership which was probably conveyed to purchasers. But I don't know what the CC&Rs and purchase documents for that property actually say. It seems like a good way to really alienate owners. If true, owners would have every right to be really angry, that's a huge cost.
I think all the Vistana resorts charge a parking fee for non-ownership reservations, meaning those booked for cash or Bonvoy points through the Marriott system, or Encore Package reservations. But there are no parking fees for ownership reservations, including exchanges via II, VSN or Abound. I will be surprised and dismayed if that is changing.
I hope the person you spoke with was just confused or misinformed.