The AI problem isn't going away. But if universities decide to shift its burden and consequences entirely on the students, then the situation will become untenable. We don't know the other side of the argument here. Regardless, it's a serious concern that the university refuses to supply the accused with the evidence (are they trying to emulate the bigtech now?). One thing the universities must recognize is that academic integrity and ethics won't survive as a unilateral policy. Practice what you preach.

The university’s “evidence” in this case is “Turnitin said so and computers are never wrong.”

I think we need to accept that AI is here now. Just assume that any take-home assignment can be done with AI.

If you want to test non-AI skills give them pen, paper and a room without cell reception.

It's not fair to students to assume they used AI based on scant evidence. Just assume everyone uses AI.