authorOrCollabsId-has suppresses show_private

[Enthalpy]

If an authorOrCollabsId-has search is run, adding &show_private has no effect.

[Enthalpy]

authorName-is similarly suppresses private trials, somehow.

[Arnaud Vié]

And I guess all other search fields do.

FYI, you are only an admin in the English section, so you can only view private trials if the search criteria include "criteria[language-is]=en" as per search_engine.php#l17.