I have also wondered if the carts have made them unsuspectingly more vulnerable to apostates.....To a point I think Wt has given power to the apostates and has made the R&F more accessable.
I am befuddled by cart witnessing. I live on an avenue that has heavy foot trafic (it runs along the shore). Every night and every morning, they are stationed across the street from my apartment. No one talks to them except other Witnesses that pass by.
Whenever I see them, they are just standing or sitting, either talking to each other, no one or to other JWs.
Also, it's not just the avenue along the beach. In my neighborhood alone, they are in front of the supermarket, in front of the health clinic and they set up in at least two locations on the avenue along the beach. I pass them by every night because I go walking at 6:30 PM. They are always at two points on the avenue.
I would call them pests but they really aren't bothering anybody. Literally.