Ridge soaring in the French Alps (local to the airfield, waiting for an
improvement in the weather) with a very experienced pupil handling. He
started to turn right; I automatically glanced right, Flarm beeped, I
glanced down and straight back up to find the daylight blocked out by the
underside of X's glider in what appeared to be 60 degrees of bank,
overtaking us and climbing.
Later I discussed it with X on the ground: he had spotted us on his "Flarm

Radar" moving map and thought he would nip over and say hello!
Unannounced, he zoomed from behind and below us, "knowing" that we
"would not do anything stupid" because (he assumed) we would know he
was there. But the first that we knew was that beep, perhaps 2 seconds
before impact by an aircraft that we could not have seen (behind and
below) - but for X's quick evasive reaction.
Interestingly, X explained to me that I shouldn't rely solely on Flarm for

collision avoidance!! Draw your own conclusions!
J.