Don,

I fully agree that maintaining a good lookout at all times
is a good basis for see-and-avoid.

However, we believe that even the best pilot may occasionally fail to detect traffic.
There are a number of human factors which affect perception
(distraction, selective attention, target merging into background, target not
moving wrt. background, etc).

We have a presentation where on one slide we listed the situations where FLARM
has potentially better and/or earlier chances to detect traffic than the human eye.

These situations a
- Head-on and converging course (both gliders in cruise), especially in the
presence of clouds, snow fields etc.
- One glider circling, another one approaching the same thermal.
- Two gliders circling in opposite directions (yes, we know this shouldn't happen...)

As you say, the fewer gliders in a thermal, the more helpful FLARM can be.

FLARM does help in wave, but the indicated relative bearing to the threat may be strongly biased by wind.

Needless to say, whenever a FLARM warning occurs, the pilot should immediately
try to make visual contact with the threat.

In the Classic FLARM manual, we write:

"Under no circumstances should a pilot or crewmember adopt different tactics or deviate from the normal principles of safe airmanship."

I think that summarizes it quite nicely.

Best
--Gerhard