Eric Greenwell wrote:

Even better is to avoid the collision in the first place. The Europeans
now have an additional choice beyond "see and avoid": the "Flight Alarm"
device from www.flarm.com. Over 450 of these devices have been
delivered, and 2000 more are scheduled for delivery this year.

But this device (whether useful or not, we will see) will never be sold
in the USA. An excerpt from the manual, translated from German:

FLARM must not be used in the USA or in Canada or by US or Canadian
pilots or in aircraft which are immatriculated or insured in the USA or
in Canada. The use of FLARM is forbidden when there are persons on board
who live in the USA or in Canada or who are citizens of the USA or
Canada. The use of FLARM is forbidden when the place of departure,
destination or of any intermediate landing is in the USA or in Canada.

Guess why!

Stefan