> The author says you should assume the time zone of where you will be when that time occurs, but that's certainly not a safe assumption
It's not even assumption which is guaranteed to have a unique answer, much less the correct unique answer. It's possible for a person to experience the same time local time (on the same local date) in more than one time zone when travelling.
Heck, it's possible to experience the same local time on the same local date twice without travelling during DST or Summer Time transitions, and while most people don't have events scheduled then, people who do might work might.
It's not even assumption which is guaranteed to have a unique answer, much less the correct unique answer. It's possible for a person to experience the same time local time (on the same local date) in more than one time zone when travelling.
Heck, it's possible to experience the same local time on the same local date twice without travelling during DST or Summer Time transitions, and while most people don't have events scheduled then, people who do might work might.