Businesses are trying to capture the added value of a Del Mar reference. I often see "La Jolla" businesses that are located in Clairemont and University City, same issue.
@Jessica Nguyen, exactly! How unfortunate! :( Del Mar sounds so wealthy and like a tropical resort! I was looking into buying in the Carmel Valley area and If I did I only wish I would have been able to say I live in Del Mar. lol
In general though, if you think of Carmel Valley east and Del Mar west, you should be just fine.