I think it would be good to know if there is a written policy about when an itinerary is recognized as no show. From what I am reading it seems like an agent who notices that a ticket has not been lifted at some random time when they have another customer looking for seat can perhaps no show it and sell it again. That, if true, is very bad practice. But of course since Amtrak almost has the inside track on many bad practices, I suppose that might be par for the course.
I don't think Amtrak ever bothered to figure this out when they introduced the e-ticket policy (which was, as I recall, expanded nationally completely out of the blue). I remember that when they introduced the no-show cancellation policy there were a slew of posts over the course of the first few weeks of the policy where two things were going on:
(1) Tickets weren't scanned on a short leg of a crowded route, and then the whole trip got cancelled out (sometimes after the second leg had been boarded, the third leg would still cancel out). An easy example would be someone connecting from the Hiawatha to Chicago, but I seem to recall a few cases of "Passenger boarded the Capitol Limited somewhere, got recorded as a no-show, and when they got to Chicago their reservation onward had been cancelled out from under them".
(2) Something got crossed up between (say) an SCA and a conductor in terms of who boarded or didn't late at night (potentially due to a room swap).
(3) Passengers who were used to being able to board a stop or two downline due to (say) traffic issues (e.g. WPK for ORL, ALX for WAS), if not outright skip a leg out of convenience (again, traffic issues and the like) were getting cancelled out.
(There was one case where I got stuck chasing the
Hoosier State from Indianapolis for a few stops, and the conductor [Phil Streby of the RPA Board was the conductor that morning, as a fun side-note] had to
un-cancel my ticket.)
The latter was arguably on the passenger (I say arguably because prevailing practice on Amtrak had been that this wasn't the case because of the paper tickets), but the former two were on Amtrak botching the rollout.
IIRC Amtrak ended up sending out a memo to SCAs and the like saying "Look, if you think someone has no-showed for a sleeper trip, make sure they've
actually no-showed and hold your horses because those tickets are expensive and this is causing problems".