This post from Americans for the Arts shows why arts education needs to be part of a full-time curriculum rather than just on occasion.
If we took math out of the school curriculum, and replaced it with a six-week outreach program from an external organization, should we expect our children to develop a knowledge of math?
Of course not.
Then, why do we do this with the arts?
Many schools have responded to cuts in arts education funding by relying on temporary arts programs in place of investing in an arts teacher for their school.