I just noticed this as part of Emvoice's Terms of Service for its synthetic singing software, and it is concerning, especially since their product depends on live, account-based access to their servers:

Emvoice commits to preclude use of Emvoice One Recordings and Content for political messages, or defamatory or derogatory lyrics. Content of this nature will not be available as part of the Emvoice product or service line. Neither Emvoice nor Users shall share any Emvoice generated Content that is unlawful, harmful, threatening, abusive, tortious, defamatory, libelous, vulgar, lewd, profane, invasive of another’s privacy, or hateful.

Taken at its face value, this would allow Emvoice to shut me down in mid-song if a moderator detected that I was having their servers sing favorably about a political candidate, or render unacceptably raunchy lyrics, or deny the existence of God.

In fairness, though, I can certainly understand them not wanting to be used to voice a virtual Johnny Rebel.

I'm not going to sweat this, but it does bother me somewhat.