@MPhilofsky do you know if these recommendations were ever discussed further and/or recorded as conventions anywhere? if no (and if you agree it’s THEMIS-worthy), i’d be happy to “sponsor” the discussion. let me know 
[I checked CDM docs and all I find is this note on observation.observation_start_date: “For some observations the ETL may need to make a choice as to which date to choose.” Also don’t see anything on this topic in the THEMIS repo.]