That said, how are you checking for AI? My sister who taught high school ran into this problem when she realized that AI detecting software isn't perfect by any means.
AI is pretty much the death of the written essay as an assessment.
Mostly Universities use a software submission platform such as
Turnitin. Turnitin's big benefit is that has an automatic plagiarism checker, but it has also added an automatic AI checker last few years. No AI checkers are that good. The biggest problem with AI checkers are going to pick up false positives if students have used some form of assistance software like Grammarly. The language style of AIs is very plain: precise, clean, short sentences, no spelling and grammar errors, just like Grammarly will convert writing into (I mean the basic Grammarly - there's also an advanced form which has generative AI). It may even flag a student who has developed a superior academic writing style. What it can be most useful for is a screening, "first pass" for things to scrutinise more closely.
So then we examine more closely with academic judgement, and there are various criteria we can use to consider. For academic judgement, most universities by now will provide criteria to check by. Some might have these available. You can look around at some suggestions of typical AI habits (
e.g. Wikipedia has one) but good luck finding the time to do that level of analysis and getting a good enough case. Even if we were that good at spotting AI - and we're not - the time it takes is likely unsustainable in workload.Most students cheating with AI are smart enough to not make major errors like also copy and pasting the AI prompts and other major giveaways. Fake academic references that don't exist is usually one of the most common giveaways I've encountered that make for a strong case, but that's more a university thing (school projects don't tend to have referencing). Sudden major changes in writing style or quality if you have an example of a student's previous submission is a potential sign.
And then with any accusation of cheating, the standard in most universities is civil law, "balance of probabilities". But that student is going to take a punishment which could have substantial repercussions, such as their degree classification, or even withdrawal. If a student really wants to fight this, you need to think whether the university will uphold it, and then potentially the law. So... how confident are you the court will agree your decision was right? How about the uni, paying all the cost of the case, plus potentially a payout if it loses? Therefore in practice the uni will lean to the student's side. There are plenty where I think there is a strong suspicion the student has used AI, but it's not going to stick so we don't pursue it.
Therefore In practice the majority of students who cheat with AI are at least moderately careful will get away with it. (They might get poor marks, of course.)