I was thinking this too, but I don't believe this is the case, and I feel like it would not be a good idea either.
Most of these people are likely students; this should be a learning moment, but I don't think it is yet grounds for their entire academic career to be crippled by being unable to publish in a top-tier ML venue.
ML reviewing is a total joke. Why do you have noob students reviewing a conference paper.
2% would be on the very low end of the number of people who lie, get caught, and become repeat offenders anyway.
If this is tolerated, it sends exactly the wrong kind of message. The students, if they are, should be banned for life. Let them serve as an example for myriads of future students, this will be a better outcome in the long run.
This didn't trip for people who were merely bouncing ideas off a LLM, they caught people who copy and pasted straight from their LLM.