However, if you intend to hitch a ride to the peak, and hike the profile, hike down, or hike the loop around the peak, you must pay the general admission fee of $18 per adult to arrive at the peak by vehicle.

As of today, July 20, 2013, the steep fee schedule to access Grandfather Mountain Park, Peak, Swinging Bridge, etc, by vehicle remains in place. Visit the website for up to date information: grandfather dot com, hours-and-rates
There are no plans to omit those fees; they now go to the not-for-profit Grandfather Mountain Stewardship Fund.

From the website-things to do-hiking
"Visitors to the Grandfather Mountain travel attraction are still able to access Grandfather’s backcountry trails from the Swinging Bridge area, which is included in the price of admission to the attraction.
Hikers wishing to access Grandfather Mountain State Park from the Swinging Bridge are required to purchase a general admission ticket to the attraction before driving to the summit."

Approx 2600 of 4000 acres was sold to North Carolina.