Saeed Maqbari (may Allah have mercy on him) says that once Sayyiduna Ibn Umar (may Allah be pleased with them both) was talking to a person, and I went and sat between them. He struck his hand on my chest and said: "Do you not know that the Prophet (peace and blessings be upon him) said: 'When two people are talking secretly, do not sit with them without their permission.'"