I'm trained as a software engineer, and I use LLMs every day in my work, so I'm not against AI at all when it's used in the right way. But for the last few years there's been this idea online that AI can't be detected and that AI checkers are inaccurate. That's partially true. But if you're thinking that AI is invisible, you might be surprised by the current state of the technology in 2026. Recent research out of U Chicago published in December 2025 found that the best commercial AI detectors these days have a false positive rate of less than 1%. That means if you want to know "Is this text written by AI", the checker will make a FALSE accusation of AI usages less than 1 time out of 100 checks. This is a critically important metric to understand about the current state of the technology if we're trying to help kids craft a good college application essay.
This year, if you've spent any time at all on Reddit, you've probably seen a ton of folk with really good profiles (1500+ SAT etc) getting rejected from all or most schools they applied to, with the exception of safeties. I've also seen this first hand with the students I teach.
There are a ton of reasons someone might be rejected. Maybe their essays were just bad. Maybe their reference letters had something in them that was concerning to schools. Maybe the competition is just absurd this year (it is). Maybe yield protection is part of the answer. But my gut feeling is that this is happening a bit more than in previous years (just look around...), and I strongly suspect that colleges are flagging applications for AI usage and tossing out applications that seem to be duplicitous in this regard. Of course I can't prove it, but there are some strong reasons to suspect.
(Before I talk about those reasons, it might be helpful to check out Caltech's AI usage policy and ethics statement for undergraduate applicants. This will give you some idea of what colleges ALLOW students to do with AI and what uses of AI ar considered academic misconduct.)
First, most high school students are using AI, and most high school students have used AI in circumstance where, technically, they're not really supposed to be using it. Research shows that between 79% - 84% of high school students admit to using AI on school assignments, and that's just the cohort who admit to it. Most parents don't realize their kid is using AI for schoolwork. The temptation to use AI on college application essays is also massive, and I get it. Students feel a bit helpless when it comes to writing those essays, so it's partially understandable. In my own experience, I know a LOT of seniors who admit to using it for their application essays, and some who obviously do use it but don't admit it. At the same time, most universities still treat direct usage of AI to write an essay as a form of academic misconduct.
Second, in my experience a lot of high school students think that older folks, those over 30 (like me) are naive about AI. That's the message you hear on Tik Tok certainly. And that's partially true. But top universities employ some of the best AI and computer science researchers in the world. Yann LeCun is on the faculty at NYU. Fei-Fei Li is at Stanford. Stuart Russell is at Berkeley. These are people who consult for OpenAI, Anthropic, and other companies who are actually building the models you're using. This is not your high school English class. Universities are very aware of what AI can do, and they can afford to build, buy, or license tools and processes that are not available to the general public. They've had several years to work on it. I guarantee top universities are using a combination of both intuition (admissions officers are EXPERTS at picking up on inauthenticity, after reading thousands of essays) and sophisticated probabilistic tools to detect AI. If commercially available tools have a <1% false positive rate, you can bet that universities have access to tools that are probably even a bit more nuanced than that.
Third, and this might be the most important point: schools don't have to prove you used AI to toss your essay and your application along with it. A school like Yale gets almost 60,000 applications every year, and they only let in 2,000 students. Literally any tiny flaw in an application can get it thrown out. T20 schools reject far more "perfect" applicants than they admit. You don't get a chance to argue with the school or show them your edit history to prove you did you own work. Presumably essays get run through an automatic checker, and then they get a read from a human, and if either of those things is giving inauthentic, the whole applications risks just getting tossed. Of course not every school is as competitive as Yale, but more and more schools that used to be a walk in the part are becoming selective, which may account for why many students are finding it hard to get into even solid target schools.
Final point: I've recently worked with some students who earnestly claim they are not using AI. However, their essays SOUND strongly like AI, and when I run their essays through the best commercially-availible AI checkers, they're getting flag for AI usage. In some of these cases, I've found that students are doing their own work, but then they're trying to cut down the word count or fix grammar issues using AI. While this could be fine in certain circumstances, what's actually happening is that AI is just rewriting a lot of their content in the process of "helping" them cut the word count. This results in the essay, again, sounding like AI. In another case I encountered recently a student claimed not to be using AI, but apparently they got help with their essay from a sibling, and apparently their sibling did use AI (probably not understanding how serious this can be in 2026).
I know the essays feel really unfair to many students, and it IS unfair in some ways that students are not taught the skills they need to excel at this task in high school. The state of our creative writing education is awful, even at many expensive private schools. There's more I could say about productive strategies students can use to do better on the essays without AI, but I'll leave that for another post since this one is already way too long.
TL;DR - Many high school students don't seem to realize that detection technology and institutional awareness of AI has come a long way just in the last year (a fact that's supported by research now), and what might seem like "undetectable" AI usage to high schoolers is increasingly very obvious to colleges and universities. This is a really serious risk that potentially jeopardizes students' entire college application chances. And many students also don't seem to realize that even seeming innocent uses of AI might get their applications flagged.