Note this would be illegal (under the term that requires you to provide all resources specifically relating to the exam as opposed to the subject in general to external students).
It would also cause students to appeal, and the statistics would be obvious enough that the appeals committee would investigate, ask for the mark scheme, and would quickly find on the students side because the paper clearly contains arbitrary details designed to do this.
Note there’s a lot of things that are like this in law, where people could in theory cheat, possibly even within the letter of the law, but they don’t because the courts throw the book at them when they do.
Note this would be illegal (under the term that requires you to provide all resources specifically relating to the exam as opposed to the subject in general to external students).
It would also cause students to appeal, and the statistics would be obvious enough that the appeals committee would investigate, ask for the mark scheme, and would quickly find on the students side because the paper clearly contains arbitrary details designed to do this.
Note there’s a lot of things that are like this in law, where people could in theory cheat, possibly even within the letter of the law, but they don’t because the courts throw the book at them when they do.