I reserved a site on recreation.gov in June for my trip to Yosemite in October. Got to the campground to find a sign saying the campground is closed for the season and reopens in May. No host, bathrooms locked, and water spigot turned off. I'm all for primitive camping but prefer to be aware of what I'm getting into. Also it felt a little unsafe at first- not knowing the area and given the out of the way location and the lack of a host. We drove up to Yosemite but by then all the other campgrounds were full. People would show up and camp for free without reservations. It could have really messed up my otherwise well-planned trip had all four of the sites been claimed by squatters. Still haven't been able to find anywhere online or otherwise that would have hinted the site would be closed. My advice: in the off season camp for free and you'll have a 5 star experience. I, on the other hand, will be looking to see if I can get a refund.
Update: A week or so after we returned home from our trip I received an email stating that the campground had closed from October until May 2019 due to flash flooding concerns, and all reservations were refunded. Thanks for letting us know before our trip, recreation.gov...