There is not a limitless amount of bandwidth to broadcast in a small area. Most of these devices are operating in the same spectrum (since they are WiFi, UHF and SHF). The FCC almost certainly has the exclusive legal right to regulate the radio spectrum, but the organizer of an event should be given some way to coordinate and organize access to the limited resource. That the FCC lacks any way for an event to legally do something that I believe they should be doing. I argue that the FCC needs a form and a fee for this sort of thing before organizers are allowed to restrict WiFi access. And that requests are temporary and limited to santioned events and not for a coffee shop or theme park that wants to gouge customers.
Of course I'm ignoring the issue of free speech. Does your right to free speech include running your own WiFi network to circumvent a potentially malicious organization's WiFi?
$200 per head seems about right on price, if I had to hire some consultants to throw together a network for 3 days, then tear it all down, seems like a bargain.