E/CN.4/2001/83 page 14 55. Vulnerability therefore has to be regarded as a characteristic of migration. It should be seen not as a weakness, but as the fact that, because of the special circumstances in which migration is now taking place, migrants are exposed to smuggling and trafficking and may fall into the hands of organized gangs which take advantage of their need to find work in order to survive, and all of this is directly related to the lack of documents which could regularize their situation. This lack of documentation makes them extremely vulnerable to getting caught up in trafficking networks and clandestine activities involving, for example, degrading sex work and slavery-like domestic jobs. 56. In many cases, clandestinity is thus the situation in which migrants find themselves as a result of poor information, lack of documentation, blackmail or fraud. When they become clandestine, many of these persons are forced to conceal their cultural identity and other basic indications of identity for fear of being reported or discovered. In this connection, we cannot forget that, in many cases, these persons left their homes with illusions which were destroyed when they arrived in the host countries and which often make them deny the true situation in their communications with the families they have left behind. This situation is physically and mentally very serious for the individual, who is forced to deny his own identity. 57. An analysis of the question of migration thus also has to deal with the category of undocumented migrants. As soon as this category becomes applicable, it becomes synonymous with lack of protection. Many migrants now referred to in discriminatory terms as being “illegal” used to be called refugees, displaced persons, returnees and reintegrated persons and are now a fact of life on all continents. 58. Citizenship is the key to questions and issues relating to the concept of migration. It must be borne in mind that non-citizenship is handed down by migrants in many countries to their children. The lack of access to identity documents is common for children and adults who do not have documents or whose documents have expired. This characteristic is linked to the above-mentioned element of vulnerability. The lack of documentation is the cause of vulnerability to contractors and subcontractors of undocumented labour who take advantage of the need for migrants, who are hired for unfair wages, hide their accent or identity in order not to be discovered and are constantly threatened with being reported to the migration authorities. In this vicious circle, discrimination against migrants and unfairness to them only become worse. 2. Sale of fraudulent documentation 59. The Special Rapporteur draws attention to the following groups of persons who are of particular concern to her because they have no protection. Special attention must be given to persons and groups of persons in irregular situations who are undocumented and who are the victims of trafficking agents who have sold them travel documents. Another matter of concern to the Special Rapporteur is the monitoring of the rights of other groups of migrants who are in detention or living clandestinely and who are subjected to discrimination and the denial of their rights and thus lacking in any legal, social and political protection in the places where they live. 60. In the Special Rapporteur’s opinion, all these persons are covered by the definition of migrant, which should take account of whether a decision to emigrate is voluntary or not. As the Special Rapporteur showed in her first report, whether or not displacement is voluntary, to the