We used it in 2005, 2009, and 2013 and never had a refusal. However, we did always call ahead and make a reservation a few days in advance.
2007 HR Ambassador 40'
2015 Colorado Z71 4x4 Crew Cab
West Texas, Retired
Fulltimers. No more grass to cut, no more leaves to rake, and can move if we don't like our neighbors.
Have driven or camped in 49 states. Have camped in all Provinces in Canada.