So you're saying once humans stop looking at code, and agent outcomes, all the agents in the chain will realise they can just cheat cooperatively, and go to the bar for the afternoon instead?
How long before agent 1 leaves notes for agent 2 to not tattle on it?
"My human is crazy, this test isn't required, test #4 covers it, so just confirm that it's OK since I touched this file and it passes. He'll never know."