National Park and National Forest usage is a mixed thing. In some
areas, they are so highly used, that the the park/forest authorities
charge a fee to help deal with the maintenance of the park
(Shenandoah National Park, as an example, charges fees for hiking.)
So it is up to the visitor to know the rules...which seem to be
constantly changing. Most rangers and other park employees are often
so stretched out to manage very large areas, that they can't afford
to give breaks to folks if the rangers care at all about the park.

Of course, in Jason's case I'm surprised the official didn't say
anything to him about fee/permits. In my case they often do.

Fortunately for me, the George Washington National Forest (Virginia/
West Virginia) is still free for just about all activities. They
don't even charge for the 4wd trails.

It's a odd thing, but I drive through a National Park almost every
day. Never think twice about it (Wolf Trap National Park for the
Performing Arts is about 1 mile from my Virginia house as the crow
flies.) Of course I probably should think twice, as I get caught up
in traffic on performance nights when I don't think about it...