[colechristensen]

>If an event happens and you need to tie your timestamped event logs to the 'greater reality' in some legally binding way there's (AIUI) no way to do that.

TAI (Temps Atomique International), is UTC without leap seconds and is the source of truth for "what time is it"

I'm finding conflicting reports of being able to actually use TAI on linux but there are several claims of at least specialty setups existing. You would absolutely not want smearing or anything like that in your time synchronization software in this case.