We had a first-semester freshman year course that all incoming students were required to take. The first assignment in that class was an essay, pretty typical stuff, I don't even remember what about.
A day after handing it in, roughly half of the class would be given a formal academic citation for plagiarism. That half of the class hadn't cited their sources. "This one time only", the citation could be removed if the students re-submitted an essay with a bibliography.
While it was obvious, in hindsight, that the point of the exercise was to get you to understand that the university took plagiarism seriously, especially with the "this one time only" string attached, it felt dishonest in that nobody ever came out and said so. I luckily wasn't on the receiving end of one of those citations, but I can only imagine the panic of a typical first-semester freshman being formally accused of plagiarism.