Because nuns are bad ass, and bad ass people go under cover.
According to the Huffington Post, an army of religious sisters are rescuing victims of human trafficking by posing as prostitutes to infiltrate brothels and buying children being sold into slavery. This under-cover 007-style of doing the Lord's work is expanding to 140 countries. (It's currently at 1,100 nuns operating in about 80 countries)
The group, set up in 2004, estimates ONE PERCENT of the world's population is trafficked in some form, which translates into some 73 million people.
Of those, 70 percent are women and HALF are 16 or younger.
"These sisters do not trust anyone. They do not trust governments, they do not trust corporations, and they don't trust the local police. In some cases they cannot trust male clergy," said John Studzinski, the philanthropist who chairs the nun organization (now called Talitha Kum) stressing that the group prefers to focus on their rescue work rather than promotion.
"They work in brothels. No one knows they are there."