Welcome! More devils advocate ...
No offense, but your solution for ID of 'placement tester' also flawed ... matter of fact, just about any approach taken has some potential flaws/un-intended consequences.
Even what I suggested has/could have issues.
Case in point ... found easily via Google:
https://www.edutopia.org/article/why-students-cheat-and-what-do-about-it
Section from above:
Technology Facilitates and Normalizes It
With smartphones and Alexa at their fingertips, today’s students have easy access to quick answers and content they can reproduce for exams and papers. Studies show that technology has made cheating in school easier, more convenient, and harder to catch than ever before.
And one shouldn't believe that applies to only secondary/college/uni students either. If such things are tied to 'promotions' or 're-certification' in medical fields, as examples ... comes with more incentive ... built in.
Again ... 2 cents.
'SoS', Ken