The truly insidious effects are when the content of the stories changes the reward but not by going through the standard quality-evaluation function.
For instance, maybe the AI figures out that the order of the stories affects the rewards. Or perhaps it finds how stories that create a climate of joy/fear on campus lead to overall higher/lower evaluations for that period. Then the AI may be motivated to "take a hit" to push through some fear mongering so as to raise its evaluations for the following period. Perhaps it finds that causing strife in the student union, or perhaps causing racial conflict, or causing trouble with the university faculty affects its rewards one way or another. Perhaps if it's unhappy with a certain editor, it can slip through bad enough errors to get the editor fired, hopefully replaced with a more rewarding editor.
etc etc.
The problem with these particular extensions is that they don't sound plausible for this type of AI. In my opinion it would be easier when talking with designers to switch from this example to a slightly more sci-fi example.
The leap is between the obvious "it's 'manipulating' its editors by recognizing simple patterns in their behavior" to "it's manipulating its editors by correctly interpreting the causes underlying their behavior."
Much easier to extend in the other direction first: "Now imagine that it's not an article-writer, but a science officer aboard the commercial spacecraft Nostromo..."
The argument that AIs provided with a reward channel will observe their controllers and learn to manipulate them is a valid one. Unfortunately, it's often framed in a way that feels counterintuitive or extreme, especially to AI designers. It typically starts with the standard reinforcement learning scenario, then posits that the AI becomes superintelligent and either manipulates the controller with super-social powers, or breaks out and gains control of its reward channel, killing or threatening its controllers.
And that is a fair argument. But conceptually, it leaps from a standard reinforcement learning scenario, to a science-fiction-sounding scenario. It might help to have intermediate scenarios: to show that even lower intelligence AIs might start exhibiting the same sort of behaviour, long before it gets to superintelligence.
So consider the following scenario. Some complex, trainable AI is tasked with writing automated news stories for a student newspaper. It trawls the web and composes its stories, then gets reward and feedback from the editors. Assume there are two editors for this newspaper, and they work on alternate days. The two editors have somewhat different ideas as to what constitutes a good story, so their feedbacks are different. After a while, the AI finds that it gets higher reward by using a certain style on Monday, Wednesday and Friday, and another style on Tuesday and Thursdays - this is a simple consequence of its reward mechanism.
But the rota isn't perfect. Sometime the Monday editor will edit a story so late on Monday that it's Tuesday, and sometimes the Tuesday editor will be up early and edit a story at the same time. This pattern is more common during the holidays, when the editors go to different time zones, often travel, and become more irregular in their editing.
So if the AI complex and skilled enough, then, simply through simple feedback, it will start building up a picture of its editors. It will figure out when they are likely to stick to a schedule, and when they will be more irregular. It will figure out the difference between holidays and non-holidays. Given time, it may be able to track the editors moods and it will certainly pick up on any major change in their lives - such as romantic relationships and breakups, which will radically change whether and how it should present stories with a romantic focus.
It will also likely learn the correlation between stories and feedbacks - maybe presenting a story define roughly as "positive" will increase subsequent reward for the rest of the day, on all stories. Or maybe this will only work on a certain editor, or only early in the term. Or only before lunch.
Thus the simple trainable AI with a particular focus - write automated news stories - will be trained, through feedback, to learn about its editors/controllers, to distinguish them, to get to know them, and, in effect, to manipulate them.
This may be a useful "bridging example" between standard RL agents and the superintelligent machines.