"The Interior Department broke federal spending law when it dipped into national park fees to keep its most popular sites operating during this winter’s partial federal shutdown, the Government Accountability Office concluded Thursday.
In a 17-page opinion, the GAO found that Trump administration officials violated the law by using fees parks collected under the Federal Lands Recreation Enhancement Act, which are designed to support visitor services, to fund operations and basic maintenance. This approach violated both the lands law as well as the Antideficiency Act, which imposes restrictions on how agencies can redirect money without congressional approval.
At the time, National Park Service Deputy Director P. Daniel Smith said the agency needed to divert the funds because keeping parks open but understaffed was no longer tenable."
"GAO Rules Interior Violated Law By Shifting Funds To Keep Parks Open During Shutdown" (National Parks Traveler)