Watchtower has always had a low retention rate and probably many more JWs would wander off the reservation to talk with protestors if big brother wasn't always watching guard over them. Most JWs don't want to be interrogated for being caught in the act - after all the religion is a North Korea construct.
Protestors had nice posters (Why 1914 telephone number) in LA, CA, yrs. ago standing in medium areas into parking lot. I couldn't wait to call the number when I returned home -- it was a recording and I didn't leave my name for return call -- that was my loss! I don't think standing at the entrance of conventions (whatever they're called) is a good idea. The Phoenix apostate had a flyer to hand out but crowded around other JWs coming/going made it was difficult to accept and we were racing back from lunch -- the 3 in my group enjoyed the brief hello exchanges (he was very happy) and he mentioned the "Asleep" magazine. He was friendly and kind.