I have noticed they tend to set up where there isn't much foot traffic...
...on one of my infrequent visits to Birmingham (England), they used to park their trolleys along New Street (the main pedestrianised shopping street), but the last time I went into the city, they were underneath the bypass - directly opposite a homeless man sitting about three yards away and facing them. Talk about irony. Four JW 'Christians' standing there, laughing and chatting amongst themselves, dressed to the nines, and a man, down on his luck, homeless, sitting on cardboard on the pavement.
I was running late for an appointment, otherwise I would have engaged these 'Christians' about Faith and Works...next time I need to go in, I'm going in early.