Schools are no place for weapons; any kind of weapons

Recently something interesting has happened in Canada and an important ruling was made by the Supreme Court of Canada which while I would disagree with the ruling, it is an indication of the high value the Canadian legal system gives to religious freedom.

Here is the issue:

The case stems from a November 2001 incident at Ste-Catherine-Laboure school in LaSalle, Quebec. A sikh student's cloth-wrapped dagger came loose from around his waist and fell to the ground at the elementary school while he was playing with his friends.
The principal ordered the then 12-year-old to remove the kirpan, but the student left the school rather than remove the 10-centimetre-long ceremonial dagger, which, he says, is a key component of his faith. He eventually switched to another school and his family took the matter to court.
The case has been winding its way through the legal system for four years.
In May 2002, the Quebec Superior Court ruled Gurbaj (the student) could wear his kirpan to school if it were wrapped in heavy cloth inside a wooden case, underneath his clothing.
Quebec's government at the time appealed the decision. In 2004, the Quebec Court of Appeal struck down the decision, ruling the kirpan had the makings of a weapon and was dangerous.
Although banning the weapon was a hindrance to freedom of religion, the court ruled community safety comes first.

Before I state why I disagree with the decision, I have to point our that the nature of the decision is noble and deserves credit and I solute the Supreme Court of Canada for that. However, as a secular person with a Muslim background, I believe any device that can be used as a weapon (not necessarily by the owner of the device but by anybody else), should not be allowed into public schools. I understand that in this case, the device is considered as a religious tradition, but that should not be the excuse to allow that to be taken into the schosome might tyht argue what about religious rights? Well, how if there is a religion which requires people to take machine guns, or even tanks or even bigger weapons into the school? Are we going to say it is ok because it is part of their religious tradition? You may laugh at my example as say that there is no such a religion that would require its followers to carry such weapons with them. Yeah, may be there isn't. But how if I create one? Religion doesn't need to be old and traditional and doesn't need to have millions of followers to be called a "religion". Really, what defines "religion" and who determines if "this" is a religion and "that" isn't? I am not against allowing people to use and carry their religious items, as it should be considered a personal choice, but I am absolutely against allowing people to bring into schools or confined public spaces the devices with the potential of being used (by anybody) as a weapon.

In my opinion, the recent ruling, although respectable in nature, is a potential slippery slope which in the future cases can be argued as a precedent in Canadian legal system and as a result of referring to that ruling, any potentially dangerous act or device may be considered lawful only if it can be placed under the banner of "a religion".