ICML 2026 Desk-Rejects 497 Papers via Watermarked-PDF Sting — 506 Reviewers Caught Using LLMs After Agreeing Not To

ICML Blog·high signal

ICML embedded hidden LLM instructions in submitted PDFs to detect which reviewers were piping papers through AI despite opting into the no-LLM Policy A track. The sting caught 506 reviewers; 51 had LLM contamination in more than half their reviews and had all submissions stripped, resulting in 497 desk-rejected papers. This is the first large-scale academic enforcement action using a technical countermeasure — watermarked content that influences AI-generated output — rather than honor-system detection.