On Tue, 26 Jan 2016 15:46:55 -0800 (PST),
wrote:

.... text deleted
I suspect the only time we see that kind of concentrated traffic
here in the U.S. is around major airports/airways/navigational features
(where we either can't fly anyway or most pilots fly with heightened
awareness and concern) and at large soaring contests, the size of which
has diminished over the past 30 years. Nephi--which will almost certainly
be oversubscribed--looks to be the exception to that.

.... text deleted

Unfortuantely a mid-air collision only requires 2 aircraft. Recall the
very tragic accident at Crazy Creek on Nov 28, 2009 (NTSB Docket.
WPR10FA068A and WPR10FA068B). We lost 2 good pilots.

At Texas Soaring Association this accident was one of the prime
drivers for equipping our entire club glider fleet (10), including our
Pawnee towplanes (3), with PowerFlarm when the units were first
released to the US in 2011.

Not saying Flarm would have prevented the Crazy Creek accident, but
"see and avoid" is clearly not 100% effective.

On a busy day TSA can have two towplanes and upwards of two dozen
gliders all within a few miles of the gliderport. Flarm is cheap
insurance.

Bob