A/HRC/26/29 Canada, for example, the Government formed a special police unit to produce intelligence updates on potential protests by indigenous peoples, primarily those fighting outside development on their ancestral land. Similarly, disproportionate force (including armed police, snipers and roadblocks) is often deployed at disfavoured protests as an intimidation tactic. Such practices should be vigorously discouraged. As the Special Rapporteur has previously noted, public assemblies should be presumed to be peaceful and lawful, until proven otherwise (A/HRC/20/27, para. 25) Surveillance tactics and disproportionate shows of force attest that authorities in some Member States often presume the opposite, and have a chilling effect on peaceful protestors, such as in the United Kingdom of Great Britain and Northern Ireland (A/HRC/23/39/Add.1, para. 32). 46. In other cases, inaction by authorities may prevent some groups from exercising their right to freedom of peaceful assembly. The Special Rapporteur has received numerous reports from India regarding the disruption of public assemblies of Dalit individuals — members of the country’s traditional “untouchable” caste. This includes one case in 2009 in which members of another caste obstructed a funeral procession and beat members of the Dalit community. Police reportedly failed to intervene, despite being present. In Egypt, peaceful female demonstrators were sexually assaulted repeatedly in Tahir Square, largely due to the inaction of law enforcement authorities. In Bosnia and Herzegovina, unidentified individuals violently disrupted LGBTI events in 2008 and 2014. In both cases, the police failed to provide protection to the organizers and participants. In several countries, stigmatization and counter-demonstrations against LGBTI pride parades and marches have also dissuaded organizers from holding such events. 47. Other practices not directly related to the right to freedom of peaceful assembly may also be used as leverage to keep certain groups from freely exercising such right. Those practices include the expulsion of students from universities for participating in peaceful protests (for example, in Chile), the arrest and detention of, and excessive use of force against, peaceful Tibetan students calling for freedom to study the Tibetan language (China), the threat of revocation of residency, refugee or asylum status for participating in peaceful demonstrations, the existence of institutional obstacles that prevent demonstrators from receiving competent legal assistance if charged with an assembly-related crime (including the harassment and intimidation of lawyers who provide such assistance), and the threat of termination of employment (and legal residency status linked to employment in some circumstances) for participating in peaceful protests, for foreigners and migrants. D. 1. Challenges to the enjoyment of the right to freedom of association by groups most at risk Legislation governing freedom of association that contains explicitly discriminatory provisions 48. Legislation that explicitly excludes individuals or groups from forming associations on the basis of prohibited grounds constitutes a violation of the rights of those groups. For example, migrant workers are explicitly prohibited from forming trade unions in Singapore, and they are not allowed to join or form unions in the Plurinational State of Bolivia (CMW/C/BOL/CO/2, para. 34). In some instances non-nationals are allowed to join existing trade unions or labour associations but are not allowed to hold office in those associations, as in Singapore. However, the restriction on forming their own associations deprives migrants of autonomy and vehicles through which to advocate or promote issues of concern that may differ from those of nationals. 49. Some laws limit the type of associations that individuals or groups can join or form. The Committee on the Rights of the Child has noted with concern that in Costa Rica, the 14