Val,
Not saying that everyone takes Calc BC here (because that is not the case), but I don't think that Linear Algebra in our district is a "sparkly sticker" course. There are enough kids that excel in math (and other subjects) that such courses are warranted. The average AP score (on all APs, not just math) for last year's class was slightly over 4, so most kids know the material. Very, very few kids score under a 3. And my eldest had more than one kid in her class that did mathematical research with professors at elite schools (and had their name on published papers).

Again, not every kid, and certainly not the majority, but those who are capable are encouraged to take such classes.