First observation: Surely any entity intelligent enough to hack the essay according to the rules you have set is also intelligent enough to get the maximum grade (much more easily) by the usual means of writing the assigned essay…
Second observation: Since the concept of “being on topic” is vague (essentially, anything that humans interpret as being on a certain topic is on that topic) maybe the easiest way to hack it following your rules would be to write an essay that is not on topic by the criteria the designers of the exam had in mind, but that is close enough that it can confuse the graders into believing it is on topic. An analogy could be how some postmodernists confused people into believing they were doing philosophy...
On the point that any AI smart enough to do this could write a 12 essay: remember that you don’t know the essay topic in advance. You only have 25 minutes to write, while if you do one off-topic, you have more time.
First observation: Surely any entity intelligent enough to hack the essay according to the rules you have set is also intelligent enough to get the maximum grade (much more easily) by the usual means of writing the assigned essay…
Second observation: Since the concept of “being on topic” is vague (essentially, anything that humans interpret as being on a certain topic is on that topic) maybe the easiest way to hack it following your rules would be to write an essay that is not on topic by the criteria the designers of the exam had in mind, but that is close enough that it can confuse the graders into believing it is on topic. An analogy could be how some postmodernists confused people into believing they were doing philosophy...
On the point that any AI smart enough to do this could write a 12 essay: remember that you don’t know the essay topic in advance. You only have 25 minutes to write, while if you do one off-topic, you have more time.