Another solution is "floating time" which disregards timezones entirely. This is an option in iCalendar datetime formats.

In floating time, 10:00 in Chile is "10:00 in Chile". No timezone offset.

https://www.ietf.org/rfc/rfc2445.txt

https://scottworldblog.wordpress.com/2009/02/20/how-to-miss-...