Dear Mr. Sweigert:
I'm an intermediate skier and cyclist and agree, in theory, with practically everything you said in your column on Feb. 27, "Know the code for your safety."
The practice of calling out your intention to pass works well in cycling where the closing velocities are rather low, the acoustic environment is benign and both riders are more or less going in the same direction. I believe, but have no data, that ski collisions often happen when the closing velocities are large, the acoustic environment degraded by wind noise and ear coverings, and both riders/skiers are going in markedly different directions (and most probably not even aware that the other person is on the slope).
But the basic underlying cause of all of these collisions is, I propose, what the military would call a lack of Situational Awareness.
Ideally, every skier should know the position and velocity vector of every other skier in his area of concern. Every skier should pick his path on the basis of knowing this and factoring in what the other skier might do. To assume that the skier you are passing will not turn into you because you call out your intention to pass is courting disaster.
Personally, when the slope is populated by people skiing slower than I am, I slow down. I don't downhill ski on weekends. When the slope gets crowded, I go home or go to one of the excellent cross country resorts where crowds and collisions are not a problem.
But I'm just a 79-year-old skier trying to survive another season.