Flarm themselves have made the same point since the
beginning. See their PP presentation from 2005:

http://www.flarm.com/files/basic_presentation_en.ppt


At 22:22 25 July 2012, John Trezise wrote:
On Jul 25, 11:14=A0am, Darryl Ramm wrote:
And if I was religious I'd thank God G made it out OK.

Darryl

Having with at a "flarm mandatory" club for over 4 years,
my view is
that flarm is of little use where there are a significant
number of
gliders in a gaggle (ie contest/regatta situation) as the
alarms are
set of very frequently, but there is not the time to
identify whether
the cause is the glider you can see or someone else. All
you can
really do is ignore the alarms and keep your head well
and truly out
of the cockpit. From the video, the situation at Cambridge
appears
show a large number of gliders, reasonably low on a blue
day have
found a number of cores which are pretty close together.
Flarm is
great out on track to make you aware of traffic in the
area.

John