From another article on this same topic:
"The judges sympathized with the notion that a woman should be able to have a reasonable expectation not to have secret photos taken up her skirt when she goes out in public, but ruled that current state law does not address that. Massachusetts’ “Peeping Tom” laws, as written, only protect women from being photographed in dressing rooms or bathrooms when they are undressed. Since upskirt photos are taken of fully clothed women in public, they don’t count, according to the court."
"Under most voyeurism laws, women must have a “reasonable expectation of privacy,” which is difficult to prove when she is in public."
Source:
http://thinkprogress.org/justice/2014/03/05/3365631/massachusetts-upskirt-legal/