I am one who does report.
We 'viva' students whose work has been referred to investigation; asking them, for instance, how they came to thread together two or three complex philosophical ideas (usually unreferenced and seemingly arbitrarily connected) in response to the assessment brief. Needless to say, the students don't see the questions they are going to be asked beforehand.
If they are the genuine author, they should be able to explain exactly how they a) discovered those links - which sources they were referenced in and why they remained without citation, in which case (at a serious push) this could be flagged as a study skills issue. Or. b)., they should be able to explain exactly how they arrived at those ideas and made the links between them independently. They should also be able to tell us exacly how such ideas fit in with the central thesis of the essay. If they can't do that - and in an AI generated essay it's unlikely that they'll be able to - they will be referred to a disciplinary panel.
It's lengthy work and it's time-consuming, and we have gluts of material to mark and I well understand why some colleagues lack the time and the heart to go through this process. In some senses I can't say I blame them; it does feel we are fighting a losing battle.
However, the alternative is 'degree by bot'. This is essential work which we have a responsibility to do. The HE system is already going to hell in a handcart without being aided and abetted by us.
It's safe to say that this job is losing its hold. All this is profoundly depressing and British universities are certainly not what they were. I did not complete a PhD to expend my time and professional energies in this way.