What is the mysterious customer of the property? What's the role? Can you give a brief introduction?

Generally, a third-party consulting agency hired by a systematic and large-scale property company conducts an objective and fair social survey from a third party in the community managed by the company, and the mysterious guests of the property grade the research results according to the corresponding grading items. The mysterious guest of property is a social investigator temporarily hired by a third-party consulting agency.