Since Kupelwieser, as director of the Kärntnertor Theater, had experience dealing with Prince Metternich's censors, he appears to have engaged in self-censorship to avoid difficulties with the libretto.
Since Kupelwieser, as director of the Kärntnertor Theater, had experience dealing with Prince Metternich's censors, he seems to have practiced self-restraint to avoid issues with the libretto.