OP's hand-out isn't 100% inaccurate ... but it goes to show the campground wifi is not very robust or intelligent. the management probably went to best buy and bought the cheapest router they could get, and just plugged it in, without reading (or understanding) the instructions.
For some reason, most wireless access points (and routers) default to WiFi Channel 6 out of the box. The more devices occupying the channel, the worse everyone's WiFi experience will be. There are 11 2.4 gHz WiFi channels authorized by the United States for use in North America, but almost everyone always lands on 6.
A well setup commercial system will have a bunch of access points and a WiFi controller, which manages the access points. If a channel is crowded (like 6), the controller will reconfigure access points automatically to use open channels.
In the config of any wifi access point I've ever laid hands on, there is an option for SSID BROADCAST (I think the FCC mandates this option). Turn off broadcast and your router is now invisible to anyone without a spectrum analyzer.