The lawyers acting on behalf of the WTBTS/G.B./'MOTHER' during a paedophile case a couple of years ago, have stated on record that -
a) "field ministry is not controlled or monitored by the Elders, the congregation, or Watchtower"
b) "an individual publisher's field ministry activity, including the time and manner it is carried out, is a personal matter between the publisher and his God."
See page 7 of the following court document - http://www.watchtowerdocuments.com/cases/Zalkin-Watchtower's_Points_and_Authorities_in_Reply_to_Opp_to_MSJ_12-16-11.pdf