50 Possible health and/or human rights implications of use in policing assemblies: Mechanical restraints are frequently used routinely during the detention of suspects, even when their use is neither necessary nor proportionate. The use of mechanical restraints on large groups of people when mass arrests are made during public gatherings could violate international use of force standards, particularly when law enforcement officers fail to use them only when they have sufficient reason to believe that the person placed in restraints presents a threat of harm to themselves or others, or may flee. Some restraints can easily be over-tightened to cause pain and discomfort, and can cause permanent injury, including nerve damage (some models allow double locking, which reduces this risk, provided it is promptly engaged). Most “cable-tie” style disposable cuffs can only be tightened, but not subsequently loosened, which makes it very easy to purposefully or inadvertently cause the wearer severe pain and discomfort. They can also cut into the flesh over time. There is a risk of secondary injuries from falls, particularly when leg restraints are used or when a detainee’s hands are tied/cuffed behind their back. Fabric restraints that wrap around the torso can potentially restrict the breathing of the detainee. The prolonged use of metal restraints can lead to lacerations, which can lead to blood poisoning and other long-term physical impairments. Fabric or other soft restraints may provide a safer alternative to metal restraints, but they must be appropriately tested and should only be used by trained personnel and in line with international human rights standards. Restraints are frequently used to facilitate torture and other ill-treatment, including through the use of painful “stress positions” and the use of additional means of force on people who are already restrained.69 Where mechanical restraints are used with the intention of causing fear or feelings of anguish and inferiority, this may amount to degrading treatment, particularly when the use of restraints is not justified by the conduct of the detainee. In the context of a public gathering, this may occur, for example, when participants are restrained and left lying in prone position, made to sit on the street for a prolonged period, tied to a fixed object. Such tactics could also be employed to stigmatize public protest and to dissuade people from joining. The European Court of Human Rights has held that 69 See, for example, European Court of Human Rights, Karabet and Others v. Ukraine, judgment of 17 January 2013.