Of course, I wasn't surprised to find the oft-misinformed Word telling us to restrict the use of that to nonhuman referents. (It's a myth that people can't be that, but it's one that many have embraced in our psychobabbling era, claiming that that is "dehumanizing.")
The usage examples, on the other hand, were a hilarious surprise. Here's the grammar checker's entry:
"Who", "That" or "Which"
Generally, use "who" or "whom" to refer to people. Use "that" or "which" to refer to anything non-human.
Instead of: She bought the desk, whom he was selling.
Consider: She bought the desk, which he was selling.
Instead of: They saw the play who got good reviews.
Consider: They saw the play that got good reviews.Could this be the honest effort of a non-native speaker, or is it evidence of a sly sense of humor lurking behind the grammar checker's sober exterior? And are there other entries with equally subversive usage "explanations"? That would be the best surprise of all.