A/HRC/15/29 complaints procedures relating to exploitation and abuse in the workplace, and in the design and delivery of social services to migrant communities.22 IV. Challenges in implementation 31. Children migrate in various ways with a variety of motives, yet the movement of children is usually considered within the framework of the migration of adults. The distinct interests, perspectives and vulnerabilities of children are thus discounted in the formulation of national migration policies and related legislation, since most of these policies operate under the assumption that all migrants are adults. On the other hand, most national childhood policies do not take account of the needs and rights of migrant children, who can be excluded explicitly or in practice from the protection of legislation and regulations put in place by Governments to protect children who are nationals of the country. Thus inadequate child protection systems and lack of effective implementation of the existing normative framework result in serious protection gaps for migrant children in every region of the world. 32. Children who migrate are also confronted by policies made on the basis of inaccurate and inappropriate assumptions. For instance, it is often assumed that all children who migrate independently have been subject to trafficking and therefore are in need of “rescue” and return to their countries of origin.23 33. Another general challenge relates to the inadequate recognition of the impact of immigration control policies on the protection situation of children in the context of migration. For example, when their parents are criminalized and subject to detention, exclusion or deportation, the children of irregular migrant parents will also suffer. The Working Group on Arbitrary Detention has asserted the principle that criminalizing irregular stay in a country exceeds the legitimate interest of States to control and regulate irregular migration, and can lead to unnecessary detention and encourage stigmatization, hostility and xenophobia.24 Moreover, there is a growing consensus that, while entering a State without a valid visa or overstaying a visa may constitute an administrative offence, it should not be considered as a criminal offence.25 34. Children, whether they migrate on their own or with their families, can be subject to high levels of physical, psychological and sexual violence within the migratory process.26 Such violence is perpetrated inter alia by both State authorities and non-State actors, while the children are being moved by traffickers and smugglers, at the border, in detention and in the workplace. Article 37 of the Convention on the Rights of the Child protects all children, regardless of location or legal status, from torture or other cruel, inhuman or degrading 22 23 24 25 26 See Committee on the Rights of the Child, general comment No. 12 on the right of the child to be heard. See Global Alliance Against Trafficking in Women, Collateral Damage: The Impact of AntiTrafficking Measures on Human Rights Around the World (Bangkok, 2007). Working Group on Arbitrary Detention, deliberation No. 5 concerning the situation regarding immigrants and asylum-seekers (E/CN.4/2000/4, annex II). See report of the Special Rapporteur on the human rights of migrants, A/HRC/7/12, para. 41, and Global Migration Group, “Rooting Migration Policies in Human Rights, Ensuring the Rights of All Migrants and Improving Human Development Outcomes”, Background Paper,( 27–28 May 2010), p. 4. See the report of the independent expert for the United Nations Study on Violence against Children, A/61/299. This study identified the vulnerability of children to violence, including children in the context of migration. In particular, the study identified high levels of violence perpetrated by police officials against marginalized groups of children, such as children living on the streets. 9