268. As regards the requirement of legality, the Inter-American Court has noted: the importance of the exercise of the principle of legality in establishing a restriction of the right to leave the country in a democratic society, given the significant impact that this restriction has on the exercise of personal freedom. Consequently, the State should define precisely and clearly by law, the exceptional circumstances under which a measure such as the restriction to leave the country is admissible. The lack of legal regulation prevents such restrictions from being applied, because neither their purpose nor the specific circumstances under which it is necessary to apply the restriction to comply with some of the objectives indicated in Article 22(3) of the Convention have been defined. It also prevents the defendant from submitting any arguments he deems pertinent concerning the imposition of this measure. Yet, when the restriction is established by law, its regulation should lack any ambiguity so that it does not create doubts in those charged with applying the restriction, or the opportunity for them to act arbitrarily and discretionally, interpreting the restriction broadly. This is particularly undesirable in the case of measures that severely affect fundamental attributes, such as freedom.299 269. With respect to the requirement of necessity, the Commission observes that precautionary measures that affect personal liberty and the right of movement of the accused should be exceptional, since they are limited by the right to the presumption of innocence and the principles of necessity and proportionality, which are indispensable in a democratic society.300 This measure cannot be a substitute for the penalty of deprivation of liberty nor serve its purposes, which may happen if it continues to be applied when it has ceased to perform the above-noted functions. Otherwise, the application of a precautionary measure that affects the personal liberty and right to movement of the accused would be the same as anticipating a penalty attaching to the verdict, which is at odds with universally recognized general principles of law.301 270. As regards the requirement of proportionality, the Court has established that the restriction of the right to leave the country that is imposed in a criminal proceeding by a precautionary measure should be proportional to the legitimate aim pursued, such that it is applied only if there is no other less restrictive means and for the time strictly necessary to serve its purpose302, in this case that of preventing Ms. Andrade from taking flight. Along the same lines, the Human Rights Committee stated in its General Comment No. 27: … Restrictive measures must conform to the principle of proportionality; they must be appropriate to achieve their protective function; they must be the least intrusive instrument amongst those which might achieve the desired result; and they must be proportionate to the interest to be protected. ... The principle of proportionality has to be respected not only in the law that frames the restrictions, but also by the administrative and judicial authorities in applying the law. States should ensure that any proceedings relating to the exercise or restriction of these rights are expeditious and that reasons for the application of restrictive measures are provided.303 299 I/A Court H.R., Case of Ricardo Canese v. Paraguay. Judgment of August 31, 2004. Series C No. 111, para. 125; Case of Baena Ricardo et al. Judgment of February 2, 2001. Series C No. 72, paras. 108 and 115; Case of Cantoral Benavides. Judgment of August 18, 2000. Series C No. 69, para. 157; and Case of Castillo Petruzzi et al. Judgment of May 30, 1999. Series C No. 52, para. 121. 300 I/A Court H.R., Case of Ricardo Canese v. Paraguay. Judgment of August 31, 2004. Series C No. 111, para. 129. 301 I/A Court H.R., Case of Suárez Rosero. Judgment of November 12, 1997. Series C No. 35, para. 77. 302 I/A Court H.R., Case of Ricardo Canese v. Paraguay. Judgment of August 31, 2004. Series C No. 111, para. 133. 303 United Nations, Human Rights Committee, General Comment No. 27 of November 2, 1999, paras. 14 and 15.