Well, Vancouver has a full class C co-channel, so I might imagine they’d have something to say about it. Cap Peak- straight shot north to the eastern suburbs of Vancouver with nothing but low hills and salt water in the way. South Mountain- line of sight stops just 25 miles north of Seattle…the Olympic Mountains block everything north of there.
But it is intriguing, and you may be correct, Semoochie. From my understanding, South Mountain is a better Seattle signal AND less hassle to the Canucks. Maybe it is simply a $$ issue. But if they want it to be a Seattle station seems like South Mountain would be better for them. But I am not an engineer.
On the commercial side, 102.9 KNBQ broadcasts from Cap Peak, whereas KOMO-FM 97.7 and KDDS 99.3 both broadcast from South Mountain. Note that both 99.3 and 97.7 are class C north of the border frequencies; 102.9 is not. In my location just N and E of Seattle, 102.9 is unlistenable, the other two are “OK” if not swell.