I think you’re all overthinking it.
Pretty sure everyone agrees with ride start being the date/time on a docket. Overthinking. Heck yes. But .....................
The complexities arise if the ride is specified in the rules as (for example) a 4 day ride with no reference to the start being based on the 'time' in four 24 hour increments following the start.
We would all accept that an 11 pm start on a Sunday is not a waste of a whole calendar day on a 4 day ride so long as you finished prior to 11 pm on the Thursday. It's still a 4 day ride (in hours) completed over 5 calendar dates being 11pm Sunday to pre-11 pm Thursday. That example clearly indicates the confusion.
Easy to clarify, and possibly something no one has bothered with as the default is just hours per day from the start docket and not calendar days as indicated by the dates on the start and finish dockets.
Ok - Time to get back to the fishing prep. I need to start calculating how many lures I'll lose in Eucumbene this trip and have adequate spares available . No start and end dockets required.