I second your opinion. With all its obvious merits, FLARM is glider-specific. It's not seen by the GA participants.

And BTW, if everybody is so concerned with the safety (including the FLARM people), how come we don't have inexpensive FLARM receivers on the market? Why can I get a cheap, under $100, ADS-B-in devices and follow the traffic through all kinds of apps, without having myself (yet) an ADS-B-out? Why can I get a TCAS or PCAS which informs me about transponder equipped planes around me - but no FLARM signal receivers which could show the targets on XCSoar even without the PowerFlarm in my ship?

Or maybe I'm wrong? Please correct me, let me know what cheap FLARM receivers are out there, and I will be happy to start my experience with the FLARM signals and increase safety, say by 20-50% ...

in order for flarm to predict a potential collision, it needs BOTH aircraft to be transmitting information. a receive only flarm would give situational awareness, but NO collision avoidance.

Matt, could you please expand on it or direct me to a source so that I can understand better (and appreciate) how FLARM works? Is it about hardware (e..g. directional antennas) or software algorithm? My flight data is on board in my glider - right?, and from the 'receiver Flarm' I would get flight data transmitted from other gliders. What prohibits MY computer to do the needed calculations (course, speed, altitude) with regards to a potential collision? Isn't that what the existing apps for the cheap ADS-B-In are doing? I can see other aircrafts with their speed and direction, and as they get closer they change the color from blue to yellow to red and at one point alarm goes off. Why do you 'have to transmit' to receive this kind of a warning?