It seems the US has so many rules and regulations for people entering parks and forestry service land. I have read on here, in other places and personal experience that people have to apply for permits often costing money and in some cases booking in a year in advance. This is an arcane system that is outdated.
Please note that issuing permits and having rules and regulations are not only for the sake of ensuring safety, but also to limit and control the impact visitors have on popular recreational areas. Some popular trails have been so heavily used, that erosion has become a major issue.
Pete