On Monday, May 21, 2018 at 10:12:47 AM UTC-7, Henning Pedersen wrote:
It is called a flarm. We have it all The Club planes and most of The private planes. (Øsf. Denmark)

Flarm is fantastic. It's widely adopted in the US now too. My own guess is that Flarm is preventing about half of the collisions at contests where everyone has it.

Doesn't that leave plenty enough collision hazard to motivate this discussion and plenty enough reason to continue trying to fix the problem?