I have not seen or spoken with anyone who has cart witnessed, however I do agree that this could backfire.
When I think about the door to door ministry prior to the carts, we could knock on hundreds if not thousands of doors before we would come across someone who would directly challenge the message or JW belief system.
Now with cart witnessing, a JW really has a big target on them for any who wish to challenge them. They are a sitting duck for apostates and it's not as easy for them to get away as it is in their own home.
It would be interesting to know if the JW sister of 30 years has had any direct confrontations with apostates while cart witnessing. Maybe something they said hit home and the reason for her drop off in service.
Good topic SBF, and glad to see you posting back here again.