Yes. For overnight guests with reservations made 3/21 or after. There are a few exemptions:
Fort Wilderness campsites
DVC members staying at DVC resorts on cash or points
DVC members staying at non-DVC resorts on points
Apparently, disabled guests who can present a valid disability parking placard
Day guests (visitors) will get complimentary self-parking but I'd bet there will be a time limit to go along with it.