I have two steam accounts, and I was not able to see anything related to a game marked private from my second account except when family sharing was enabled between the accounts. With family sharing on I could see all private games from my primary account on my secondary (including games which were not installed on the local system).
If you have family sharing on, hold off. Otherwise as far as I know it works as intended.
I’ll have to check that out! There’s also Cachalot by Alan Dean Foster, which is an old favorite of mine. Humans give cetaceans their own planet and–without spoiling too much–shenanigans ensue.