It's actually not em-dashes, they are en-dashes, which is either intentionally to deceive (e.g., swapped) or used incorrectly. Both of which are bad, it's up to everyone to decide on which is worse coming from MITality.

Spaced en dashes – like this – are a correct and accepted typographical choice. Whether to use spaced en dashes or (spaced or unspaced) em dashes is a matter of taste or local convention, and varies from one publication to another. Other than a typo or two where the space was left out on one side of a dash, the dashes in this linked document are just fine. See https://en.wikipedia.org/wiki/Dash#En_dash_versus_em_dash

I was not claiming they are not correct punctuation/syntax. My claim is just no one uses them that frequently... When you see dozens of them in the first few pages of a document it raises suspicion.

Some authors use a ton of dashes, while others never use dashes.

This is likely an artifact of writing standards - not especially suspicious, it's like MIT Tech Review or the New Yorker using diaresis when they need to say reëducate.

Sad that people now consider basic knowledge of typography, punctuation, and orthography a sign of AI.

I am not an LLM and use em-dashes and they were house style in my last 20+ years of employment. The whole em dashes == AI thing needs to just stop.

It is more about the document containing more than sixty of them. They are a completely legitimate piece of punctuation, but even prolific pre-LLM users did not tend to go that wild with them.

I did not notice anything about the document in that regard that was worthy of note.

Speaking about style choices, I was curious why you sometimes use the 'f' from the Latin Extended-B block, U+0192, in your comments. I've never seen that before! (I'd meant to ignore it but you seem to be soliciting typography discussions...)

Probably a fat finger of some sort or it came through a copy and paste. Nothing I do deliberately.

Do you think LLMs invented the em dash? Pre LLM, em dashes were a sign of pretentiousness. Which is why LLMs learned to use them, and why a document produced by a university has plenty of them.