I've never heard of this practice and would throw the book at anyone who implemented it in a shop I worked at.

You keep both your keys, one securely and one at-the-ready.

This is fair, but I have to note, a little out of date for startups which can be 100% remote to the point of founders not having a home city, let alone one stable, secure place to stash a backup.

Yes, safety deposit boxes. Yes, family, yes friends. Yes, attorneys.

But also what I said initially.