Recently a Dutch man with an MSc (Master of Science) at the Delft University of Technology and admin of Tor-exit nodes was approached by two agents of the Dutch intelligence service, the AIVD. They wanted to recruit the man as an informant or undercover agent, who would also infiltrate foreign hacker communities. The person tells his story.
Full story: http://www.burojansen.nl/bvd-aivd/dutch-secret-service-tries-to-recruit-tor-admin/
say what you want but they do a nice job at describing what it is like working for many law enforcement agencies around the world.