I don't know if I see it ever happening. But it does make sense to do it for DVC Members (yes I am one so I may be biased).
Yes, they've already gotten our "money". But don't think for one second that they don't want more of it, and they're not getting it from us sleeping in late, lounging around the pool all day and dare I say, traveling to other places outside of Disney while staying at the DVC resort.
Getting people inside the parks are where they're going to increase their ticket sales, and souvenier sales, and food sales. And what better people to target than:
a) The people who are there most often.
b) The people who have committed to going to Disney for many of the next 50 years.
c) The people who have shown they have the financial ability to pay for the next 50 years of vacations up front.
d) The people who are most like to go stay at a Disney Resort and NOT go to many (or any) parks in a specific vacation.
By offering something simple to DVC members (and/or Deluxe Hotel) you can get this person whose committed to
Disney Vacations for many years to attend the parks more often than they might have had it not been for free fast passes, and along with this person comes their wallet/purse and credit cards.
Again, I don't think you'll see it, but to me it sure does make sense from a business point of view.