The line between the SM and Carlsbad school district lies between Bressi Ranch and Rancho Carrillo. Most but not all homes in La Costa Greens are in SM. The new La Costa Ridge (prices starting at a mere 1.2M) are also in SM.

I also agree with you that most public high school are kind of scary. San Marcos high school claims to be within one of the top 1000 in the country. I’ve never been inside but it looks kind of dumpy to me.