While I generally agree with the plausibility of what you've said overall, you're drastically underestimating the traffic and particularly the bus traffic and suh. Here are many more buses per day than you've said. I took them for years.
http://www.mbta.com/schedules_and_m...ction=O&timing=W&RedisplayTime=Redisplay+Time
The 449 adds a handful more each day.
Also people don't clam at kings beach. Plenty of people walking by fisherman's, but perhaps a bit less than kings. Much greater visibility by vehicular traffic overall (but your mention of the left side of he fish house is a good one) at fisherman's than at kings.
Thank you for pointing that out. There are buses after 7PM that run once/hour, and I believe the outbound bus is the same as the inbound bus, yes? So chances of two buses being in that area at the same time are not likely. So my thinking is since there is no bus stop directly at that point (checked the interactive map on the schedule) the bus would not absolutely certainly, but could possibly be traveling in not congested traffic, and therefore moving at a reasonable, perhaps consistent speed. Let's say 30mph (typical residential speed limit)? So what then are the chances of a bus driver or passenger seeing someone in the dark in that alleyway, on the sand, or in the water, messing with a dory, saying WTH, and calling the police?
Agreed-there are fewer people walking Fisherman's because people who "walk the beach" at LSD, Red Rock, King's beach encounter land in the form of Red Rock Bistro, Anthony's Hawthorne By-The-Sea, etc., which lends support to the possibility of there being fewer people at Fisherman's on a cold, wet, foggy, rainy night after 7PM. Her last call for help was about 6:45, yes? So I would expect any activity to be at least after 7PM.
Correct-people don't clam directly at King's Beach because the sewage outwash increases the bacterial count there. It might actually be against the law in that spot.
Any suggestion on how to check the Swampscott police log to see if anyone called in a report of suspicious activity at Fisherman's the night of November 6?