Flying today SFO-YVR on reward ticket; entered passid as both my APIS travel doc and as "known traveller" on electronic check in. No dice.
Delta, AA, USAir, UA all give me precheck when I provide my known traveller ID. Not sure if relevant, but I only carry *A gold, no others. I would have chalked this up to a transborder thing, but then again all AC flights that depart the US are transborder, so I guess I'm not trusted by AC or some other criteria didn't work out.