Now that such a model exists, I think we can expect lobbying for making this mandatory. For the children...
Once adopted this will lead to an increase in randomly locked out accounts due to model false positives, because looking for something very rare will lead to most items flagged being false positives (Bayes statistics etc.).
This blog had a few interesting articles on the limitations of these technologies
https://www.hackerfactor.com/blog/index.php?/archives/971-FB...
While this is comparing the currently used hash based approaches a classification model will have similar problems.
Recorded talk for the slides in this post.