Chinese Idiom Stories
To Mow The Grass And Scare The Snake
Wang Lu was one of the magistrates of Dang-tu County during the T'ang dynasty. He was never concerned with how he could best serve the people; all he cared about was making money.
One day, the people of Dang-tu County got together and wrote up a complaint against Wang Lu's subordiante. They described very clearly how the subordinate had taken money that didn't belong to him, and then sumbitted the report to their magistrate, asking him to punish the subordinate.
When Wang Lu read what was written in the report, he began to shake, as he realized that he himself had done almost exact same illegal things. By the time he finished it, he was sweating all over, and paralyzed with fright in his chair. He didn't know what to do about this, and he couldn't help writing on the report, "Although your goal was to mow the grass, you wound up scaring the snake."
Thus, "To Mow the Grass and Scare the Snake" is to fail to keep one's actions secret, thereby allowing others to take precautions.