If someone asks questions, voices doubts about the material in the article, challenges, contradicts, suggests alternate possibilities, he/she may be counciled at that moment by the conductor or/and be counciled after the meeting, and may not be allowed to participate. All the other obedient clones will recognise this one and make a mental note that he/she is possibly a rogue, not up to speed, or just odd. Peer pressure, subtle or strong is quite effective.
Sometimes an elder will razz or ridicule someone who has an individualist tendency. At times, i think it was the 70's, they have instituted programs sort of like the block parent program. The stronger, more mature ones would be assigned to a weaker, newer one as a mentor or pace horse. They would go in service together, spend some social time, etc, all w the purpose of bringing about a closer conformity/more wt activity from the slacker.
Also, jw's are encouraged not to spontaniously go from door to door. They are encouraged to follow the group door to door plans arranged by the elders of the congregation. The person leading this group meeting organises who goes w whom, and where they go.
All a congregation's territory is broken down into small map parcels and placed on cards. Then someone desiring to do some door to door must ask for one of these from the person in charge of them.
There are also a few other methods, but these give an idea how everything is directed from the top down. Dubs learn to be good followers.
SS