the rights and freedom of the others.290 In the context of victims who are placed in shelters, further issues arise over whether detention in a shelter is provided for by law, is consistent with other rights and is necessary to protect victims.291 The prohibition on arbitrary arrest or detention is foreseen by ICCPR,292 and is also provided for in other human rights treaties293 and OSCE documents.294 The right to liberty is not absolute, but the deprivation of liberty must be authorized by law and be non-arbitrary. At the same time, it cannot be manifestly disproportional, unjust or unpredictable, and states must have procedural guarantees in place to deal with situations of unlawful or arbitrary detention.295 As such, the detention of victims in shelters could violate that right, particularly if it is not provided for by law, is discriminatory, is imposed for a prolonged or unspecified period of time, is unjust, unpredictable, disproportionate or is not subject to judicial review.296 Trafficked persons may be discriminated against, directly or indirectly, on the basis of their membership of an ethnic group or, indeed, on the basis of any other status. There is, therefore, an ongoing need to monitor laws, policies and practices for their discriminatory effects. A further issue is the impact of gender biases in the return process, which can contribute to the widespread reluctance to recognize or identify forms of trafficking other than the trafficking of women and girls for sexual exploitation. A failure to identify male victims of trafficking impedes their exercise of rights and access to entitlements, including those relating to return.297 Even when identified correctly, the special needs of male victims of trafficking may not be met by systems and processes that have been narrowly designed to meet the specific requirements of female victims.298 In particular, many assistance and protection services focus on victims of trafficking for the purposes of sexual exploitation, and have little or no assistance mechanisms suitable for male victims of trafficking for the purpose of labour exploitation, for example. 290  ICCPR, art. 12.3. 291  Anne Gallagher and Elaine Pearson, “Detention of trafficked persons in shelters: A legal and policy analysis”, Australian Agency for International Development, 2008, p. 14. 292  ICCPR, art. 9.1. 293  UDHR, art. 3; ECHR, art. 5.1; Organization of American States (OAS), American Convention on Human Rights, “Pact of San Jose”, Costa Rica, 22 November 1969, art. 7.1. 294  In particular, see the 1991 Moscow Document, art. 23.1. 295  Anne Gallagher and Elaine Pearson, “Detention of trafficked persons in shelters: A legal and policy analysis”, Australian Agency for International Development, 2008, p. 14. 296  Ibid., p. 15. 297  Craggs and Martens, Rights, Residence, Rehabilitation, op. cit., note 132, p. 70. 298  Rebecca Surtees, “Trafficked Men as Unwilling Victims,” St Antony’s International Review, Vol. 4, No. 1, 2008, p. 16. Part 2: Explanatory Report to the Principles 79