I just realized that How to reference material written by others reads as follows:
Plagiarism - posting the work of others with no indication that it is not your own - is frowned on by our community, and may result in your content being downvoted or deleted.
The wording "is frowned on" seems like it's too soft (and may be especially confusing for English learners). There are plenty of things that we frown on but those typically result in posts being edited with no further consequences for the user. For example, I frown on people using hyphens (-) where em-dashes (—) should be used. Can we change the wording to say simply "is not allowed"? (Also maybe also fix the hyphen thing while you're at it.)