I have friends in the city who have been involved with cart/table witnessing since the pilot "Manhattan" project. They have told me that they do "place" a lot of literature and that mostly religious crazies talk to them (trying to convert THEM!)
I asked them how many people had "come into the truth" or started attending meetings as a result of cart witnessing in the past three (or four now?) years of doing this work.
Answer: zero.