I believe this "wall clock time" approach is broken by design as it pushes the burden of figuring out timezone details to those who are not located in that particular timezone.

A fair and therefore safer approach is to decide that by protocol the legally binding time is defined in UTC.

Your system will translate UTC times to and from any given local time using the IANA time zone database which is regularly updated. End users must be aware about the UTC time, that it is legally binding, and that the local time conversions are provided as-is.

This way the time of a meeting or deadline is protected from local governments messing around with timezone changes.

Additionally, dates are rendered in ISO8601 standard format with a proper footnote to help users learn about international standards.