I've been to two national parks in the past two weeks. Both of them had "you must wear a mask" signs on the car approach to the entrance booths. I did not put on my mask and the park rangers at the booths did not mention it. In fact, at one of the parks, the Ranger asked me if I was prior military and when I said I was he immediately waived the entrance fee requirement, saving me $35. The visitor centers at both parks had the Biden Administration signs saying "plastic face shields are not in compliance with federal mask mandates here. You must wear a mask that completely covers your mouth and nose." But, I wore my silly plastic face shield (that barely covers my mouth) and no one said anything. I probably shouldn't have bothered wearing the face shield at all.