Beyond the questionable / debatable social cues, this is a potential security risk, and not necessarily for you. One common social engineering technique is to

Beyond the questionable / debatable social cues, this is a potential security risk, and not necessarily for you. One common social engineering technique is to gain credibility with a target's colleagues and friends before attempting to contact the target. By accepting invitations from people unknown to you personally you could be unwittingly facilitating a social engineering attack on a friend, colleague or co-worker.