[Quote; "Even with that, transits can be had up to days after (e.g. LAX-xSYD-BNE with LAX departure on the "last day").
As far as I can tell, if an agent or airline makes changes to a booking via a GDS, there is little up front constraining them from making changes not compliant with the fare rules".
Quote: "Were time zones - date line coming into play? How did the last departure time/date compare to the local time where the first flight happened. (all in GMT zulu time)"]
*****The flight departed SYD to HND, which was the first and last city in my itinerary. There is a two hour time difference between SYD, UTC+11 and Tokyo, UTC+9. I don't know for sure if the schedule is the same today as it was in March, but likely JL 52 departing 0855, arriving 1745.
(Apologies; I couldn't get the multi quote button to work, hence the weird format.)