NASCAR and the PGA? Sounds like more of a cash cow than a real need. So how can more controllers allow you to get more IFR traffic into a field? Do the spacing rules get suspended for big events? That would be nice to know if I'm taking my Falcon jet into HQU for the Masters this week.
Consider Lewis University Airport (LOT), near the Chicagoland Speedway: normally, it's non-towered, so IFR traffic is one at a time. Weather doesn't matter-- if there's an IFR airplane on approach, IFR departures and arrivals are both stopped until he cancels, which sometimes doesn't occur until the arriving airplane lands and the pilot calls on the telephone to cancel. Same principle applies to departures-- once an IFR departure is released, any arrivals are put in the hold, and successive departures are held until the first departure is identified and out of the way. It can be a VERY slow process.
Race weekend, they bring in a temporary tower
(http://www.flylot.com/nascar.htm). IFR arrivals no longer have to cancel, it's automatic with the tower, and controllers can make a judgement that landing is assured, allowing the next arrival to start inbound much sooner. Departures don't need to be held for the arrival, the tower can release them using non-radar separation rules or visual separation.
They can actually run departures one-after-another, by fanning them out in different directions. An entire ATC crew on the ground is dedicated to getting departures to the runway in an order that will work for that. One departure goes south, the next goes north, the next goes west, then another southbound, etc.
IFR capacity increases A LOT-- and NASCAR is happy to pay for that. It's important to note, though, that without the additional ATC resources, the airport could operate as normal and safety would likely not be impacted-- the airport would be busier, but the increase in VFR traffic isn't anywhere comparable to a fly-in, certainly not enough to justify Oshkosh-type procedures. There would just be inconvenience for the IFR's, due to the delays.
That's not the case with fly-ins, where sheer volume drives the equation. VFR traffic can't be flow controlled like IFR traffic can, so it's an issue of safety, not convenience. Since safety is the FAA's primary mission, they should provide the resources necessary to ensure it, whenever and wherever it's needed, regardless of what forces might be driving it.
We let them get away with this, what's next. Maybe a great new restaurant opens on an airport, traffic increases on weekends as pilots flock in for the $100 hamburger, the FAA declares additional ATC resources are required to maintain safety margins-- and we all find a 10% surcharge on our restaurant check because the FAA has started billing the restaurant, since they're the "event" causing the traffic...
'Tis a slippery slope we've started on....