The post excerpted below is fair and accurate, so far as my reading and
experience lead me to believe - still, it perhaps deserves some additional
context, which I'll try and provide a part of below...

Snip...

In the most demanding, lethal environment (WW2
air-to-air combat), it's an axiom that almost all pilots who got shot down
never saw their attacker. And this in planes with bubble canopies designed
for visibility, young eyes, training, and lots of motivation to see the guy
about to shoot you! See-and-avoid didn't work particularly well there - it
took lots of training and multi-ship formations covering each other's blind
spots to cut down the unobserved kills. And even then, by 1944 or so US
fighters were being equipped with a simple tail-warning radar (google
AN/APS-13 - the Flarm of the day!).


Yes, flarm is just a tool, not a cure all. So is a transponder, or a
parachute, or a hi-viz paintjob, or strobes. Or even listening to the
radio. They are all part of the toolkit needed to fly safely as long as
there is more than one plane in the air at one time.

1) The WW-II air-to-air kill "visual context" also applied to WW-I.

1a) It should be pointed out that while most informed observers from those
times (i.e. surviving combat fighter pilots!) agreed that many/most of their
kills were of pilots who never saw death approaching, in most cases the
victors also strove to not be seen! (Consider this the "4 O'clock fast twin
approaching Joe Scanning Glider pilot" scenario.)

2) I'm in complete agreement with the philosophy of the 2nd paragraph above,
except that I might re-write (for nuance's sake) the ending sentence to be:
They are all part of the toolkit needed to fly [increasingly, theoretically]
safely [from a mid-air collision perspective] as long as there is more than
one plane in the air at one time.

I think what Dan N. (and others, me included) wish to convey consists of an
admixture of ideas, including: a) there are no panaceas at all protecting Joe
(Glider) Pilot from mid-airs; b) self-preservation arguably should be based
primarily/fundamentally upon a good scan and "general pilot-centric
situational awareness," with electronics (voluntary or mandated) being
considered supplemental; c) "all those other electronic gee-whizzy-doodads"
serve useful (varying, supplemental) purposes but - arguably, except for
certain very-limited situations (e.g. near concentrated "heavy
iron"/commercial traffic locales) - ought *NOT* to be mandated by governmental
minions (if Joe Sport Pilot wishes to reasonably maintain healthy optimism for
the future of sport aviation in this country); d) there is-no/can-never-be-any
such thing as "absolute safety" to be found in the sky. No form of electronic
whizbang envisioned/available today can hope to provide such, nor should sport
pilots even be leaning in the direction of hoping that
"universally-accepted-to-be-perfect" safety *can* happen (unless you happen to
be in favor of a never-ending slippery slope of increasing costs for
ever-decreasing marginal additional utility).

In short, safety is a relative concept. If you find the idea of (say) Flarm
worthy, by all means, get it, but don't be trying to force your idea of
"relative safety" on the rest of the piloting community. (And, yes, I
recognize Flarm's efficacy depends to some extent upon "universal acceptance"
so please don't trot out that particular "justification" for mandating it.
Heavens! Even the [by nature, hugely risk averse] FAA still recognizes the
existence [and legality] of powerplanes without electrical systems.)

Bob - OK with risk, both as a pilot and airline traveler - W.