http://www.lexum.umontreal.ca/csc-scc/en/rec/html/2006scc006.wpd.html
Key points in the Supreme Court decision about the Kirpan case
26 This Court has clearly recognized that freedom of religion can be limited when a person’s freedom to act in accordance with his or her beliefs may cause harm to or interfere with the rights of others (see R. v. Big M Drug Mart, [1985] 1 S.C.R. 295, at p. 337, and Syndicat Northcrest v. Amselem, [2004] 2 S.C.R. 551, 2004 SCC 47, at para. 62).
About your chainsaw example...
35 The fact that different people practise the same religion in different ways does not affect the validity of the case of a person alleging that his or her freedom of religion has been infringed. What an individual must do is show that he or she sincerely believes that a certain belief or practice is required by his or her religion. The religious belief must be asserted in good faith and must not be fictitious, capricious or an artifice
About the Kirpan being a weapon..
46 Although the parties did not present argument on the level of safety sought by the governing board, the issue was addressed by the intervener Canadian Human Rights Commission, which correctly stated that the standard that seems to be applied in schools is reasonable safety, not absolute safety. The application of a standard of absolute safety could result in the installation of metal detectors in schools, the prohibition of all potentially dangerous objects (such as scissors, compasses, baseball bats and table knives in the cafeteria) and permanent expulsion from the public school system of any student exhibiting violent behaviour. Apart from the fact that such a standard would be impossible to attain, it would compromise the objective of providing universal access to the public school system.
Heres what they said about the kirpan being stolen and used as a weapon...
These are the conditions imposed by Grenier J
— that the kirpan be worn under his clothes;
— that the kirpan be carried in a sheath made of wood, not metal, to prevent it from causing injury;
— that the kirpan be placed in its sheath and wrapped and sewn securely in a sturdy cloth envelope, and that this envelope be sewn to the guthra;
— that school personnel be authorized to verify, in a reasonable fashion, that these conditions were being complied with;
— that the petitioner be required to keep the kirpan in his possession at all times, and that its disappearance be reported to school authorities immediately; and
— that in the event of a failure to comply with the terms of the judgment, the petitioner would definitively lose the right to wear his kirpan at school.
58 As for the risk of another student taking his kirpan away from him, it also seems to me to be quite low, especially if the kirpan is worn under conditions such as were imposed by Grenier J. of the Superior Court. In the instant case, if the kirpan were worn in accordance with those conditions, any student wanting to take it away from Gurbaj Singh would first have to physically restrain him, then search through his clothes, remove the sheath from his guthra, and try to unstitch or tear open the cloth enclosing the sheath in order to get to the kirpan. There is no question that a student who wanted to commit an act of violence could find another way to obtain a weapon, such as bringing one in from outside the school. Furthermore, there are many objects in schools that could be used to commit violent acts and that are much more easily obtained by students, such as scissors, pencils and baseball bats.
No violence using the Kirpan in 100 years that Sikhs have attended Canadian schools...
59 In her brief reasons, Grenier J. explained that her decision was based in part on the fact that [translation] “the evidence revealed no instances of violent incidents involving kirpans in schools in Quebec” and on “the state of Canadian and American law on this matter” (at para. 6). In fact, the evidence in the record suggests that, over the 100 years since Sikhs have been attending schools in Canada, not a single violent incident related to the presence of kirpans in schools has been reported.
Respondent has underscored that a kirpan could have the function of a weapon, but did not establish that a student had in fact so used it. In fact, there is not a single incident to which the respondent could point when the kirpan was used on school property or its environs — either in Peel or anywhere in Ontario or even all of Canada. Since Sikhs, and Khalsa among others, have been in this country for nearly a hundred years, this is a record worth considering.
61 The parties introduced into evidence several newspaper articles confirming the lack of incidents involving kirpans. An article published in the March 23, 2002 edition of The Globe and Mail refers to the 1990 Ontario decision and mentions that there is no evidence of a growing danger since that time. In an article appearing in The Gazette on May 16, 2002, Surrey School District spokeswoman Muriel Wilson is quoted as saying, “We have a strict zero‑tolerance policy on weapons or something that could be used as a weapon or taken to be a weapon, like a fake gun. . . .” But according to her, the kirpan is considered to be a religious symbol, not a weapon: “The key is how things are used. A pen could be used as a weapon, but we’re not saying, ‘No pens in schools’”. The same article mentions that the Peel District School Board now says that the wearing of kirpans “[is] truly not an issue” and that there “has never been an issue or incident, never a complaint or problem” related to wearing kirpans in school since the ban was lifted: “It can work and work really well”. An article published in the May 13, 2002 edition of La Presse notes that there have been no problems related to the wearing of kirpans in the schools of the Vancouver and Surrey school boards, which have large numbers of Sikh students. Finally, according to an article published in The Gazette on February 21, 2002, “Whether a Sikh pupil should be allowed to wear a kirpan to school might be a new issue in Quebec, but it is not in the rest of the country”
About wearing a kirpan on a plane...
In assessing whether or not the respondent’s weapons policy can be modified so as to accommodate Sikhs detrimentally affected, consideration must be given to the environment in which the rule must be applied. In this regard, we are satisfied that aircraft present a unique environment. Groups of strangers are brought together and are required to stay together, in confined spaces, for prolonged periods of time. Emergency medical and police assistance are not readily accessible.
Now schools...
Unlike the school environment in issue in the Pandori case, where there is an ongoing relationship between the student and the school and with that a meaningful opportunity to assess the circumstances of the individual seeking the accommodation, air travel involves a transitory population. Significant numbers of people are processed each day, with minimal opportunity for assessment. It will be recalled that Mr. Kinnear testified that Canada 3000 check‑in personnel have between 45 and 90 seconds of contact with each passenger.
Difference between wearing a kirpan in a court and a school (Kirpans are not allowed in courts)
Courts and schools are not comparable institutions. One is a tightly circumscribed environment in which contending elements, adversarially aligned, strive to obtain justice as they see it, with judge and/or jury determining the final outcome. Schools on the other hand are living communities which, while subject to some controls, engage in the enterprise of education in which both teachers and students are partners. Also, a court appearance is temporary (a Khalka Sikh could conceivably deal with the prohibition of the kirpan as he/she would on an airplane ride) and is therefore not comparable to the years a student spends in the school system.
About the Kirpan being a dangerous weapon
71 The argument that the wearing of kirpans should be prohibited because the kirpan is a symbol of violence and because it sends the message that using force is necessary to assert rights and resolve conflict must fail. Not only is this assertion contradicted by the evidence regarding the symbolic nature of the kirpan, it is also disrespectful to believers in the Sikh religion and does not take into account Canadian values based on multiculturalism.