Ha! Yes to some extent it would but that would really mean either a) we decided to run recommendations using a sparse model or b) we never validated the data or

Ha! Yes to some extent it would but that would really mean either a) we decided to run recommendations using a sparse model or b) we never validated the data or kept a watch on models when they were trained/retrained. This type of manipulation is typically likely when you're much larger and have alot of bots involved on the platform.