Yeah, I'd hope it'd be a big fine. But that there's a fine if you're caught won't necessarily deter someone who's way out in the backcountry...
And the new regulation will make it harder for the Park Service to catch poachers. As I understand it, one of the main reasons for the original regulation, which requires firearms to be unloaded and inaccessible (e.g. in the trunk of the car) was to help prevent poaching within National Parks, where it's easy, as many animals have lost their fear of humans.