Intelligent Environments provide the infrastructure to deliver Ambient Assisted Living such that elderly people can remain at home and independent for longer. An important part of an Ambient Assisted Living provision is the monitoring, detection and follow up of unsafe situations. One problem these systems have to perform that task is that they only observe the world through incomplete, sometimes unreliable, sensing devices. This naturally leads to uncertain, inconsistent and incomplete perceptions of the world. This paper shows how argumentation, a well established field in computer science, can help to disambiguate some of those confusing (sometimes even inconsistent) situations.