Just one actor having an incident and having their memory modified, they could think of ways to cover it up, blame the actor themselves, and even keep it a secret. The high-level official in the district presumably wouldn't dare to make a big fuss either.
But if the other six actors also turned into idiots, there would be no way to cover it up. Film and Television City would likely intervene in the investigation. With more people involved and things like lie detectors being used, their collective cheating would be impossible to hide.
The punishment wouldn't just be a slap on the wrist.
"Is there any way we can intervene in the script and negotiate with Li Teng? Ask him to stop suppressing the memories of those six actors and revert back to the main storyline?" someone suggested.