We don't expect books to include "Not guaranteed to make you smarter" on the label.
Though we technically expect securities to include "Not guaranteed to make you rich," it's in small text nobody ever reads. I doubt a high school student would be reading it and rethinking their major...
If you're American, you already know that liberal arts majors don't go to college thinking "people are going to pay me so much money for this degree in gender studies."