E-mailing grades illegal

I left the formal teaching profession before the advent of e-mail, so it surprises me to learn that (at least in New Jersey) it's illegal for a professor to e-mail a test grade to a college student, even if the professor has their written permission to do so. Yes, I can see that there are legitimate concerns over the privacy of e-mail. But, given that the State is also compiling an on-line data base containing the grades, addresses, and other information on every public school student in the State, the emphasis seems misplaced.