Isn't it even more important when working for Jinshi? The more comfortable (relatively speaking) she gets in his company, the easier it would be for her to make a mistake. She very much suspects already he's far more important than he should be, which might make the consequences of any mistake she makes that much greater. Plus the mightier a person is, the less valuable they'd evaluate a commoner's life. I don't believe Maomao believes Jinshi likes her or anything. In fact she couldn't care less about romantic thoughts. She only cares about poison, medicine, rare food, and occasionally mysteries.