To my understanding, Hilton Head was getting flack for not having it because people were use to Online check-in at resorts at WDW.
You can check-in online up to 10 days ahead of arrival same as WDW when you arrive, simply head to the Online Check-In Desk, where your Welcome Folder and Key to the World card will be waiting. Show your valid photo I.D., complete your check-in and you’re on your way!