We put this question to our shaykh, ‘Abd ar-Rahman al-Barrak, and he said:
With regard to the issue of summarising the curriculum, there are two issues that should be examined.
The first is: Is a great deal of material omitted from the curriculum or not?
The second is: Are exam questions based on the summary only and not the entire textbook?
If not a lot of material is omitted, and exam questions are not limited to the summary, there is nothing wrong with it. But if the summary is too extensive and omits a great deal from the textbook, and the exam questions are limited to that, then this is a betrayal of trust.
Based on that, if the teachers summarise the curriculum and prepare summaries for students to study, that is not regarded as cheating if it covers everything in the book and does not omit too much material, and if exam questions are not limited to that; rather they may be based on that summary or other material in the textbook. This is by way of focusing on and highlighting what is important in the course, and there is nothing wrong with that.
And Allah knows best.