Lost City spoke too soon. On the day of Halloween itself, Oct. 31, the 102 small Jack-O-Lanterns that make up Halloween's Front Line appears out of nowhere, and were skewered along the fence that encircles the Cobble Hill house at Strong Place and Kane Street.
The owner told me that she always brings the pumpkins out on Oct. 31 and not before. (I don't know about that; I seem to remember seeing them earlier than that.) But, anyway, she said they had been busy carving since Monday!