Just a note, there is a difference between a burqa and a hijab. A burqa tends to cover the whole body while a hijab is a headscarf that covers the face.
Actually, hijabs only cover the head. Niqabs cover the face, burkas the entire body.
Religious expression is a fundamental aspect of freedom of speech. In Canada and other various multicultural societies, exceptions have been granted under this pretense.
However, since America and Canada are built upon Christian beliefs and practices, crosses wouldn't necessarily be banned, while let's say, a burka would be. Burkas also pose safety and security threats, which is the exact reason they're banned. The exact same concept applies to kirpans, hats, doo-rags, and niqabs.
In many schools and working institutions, women of the Muslim faith wear hijabs, especially in Canada. In fact, nobody even looks twice or questions it, because it's that culturally and politically accepted and ingrained in everyday life.
Outside of specific institutions which promptly express security concerns, burkas aren't banned, nor are kirpans.
At least to my knowledge, kirpans are not banned whatsoever. They just need to be concealed at all times, once again, due to security concerns.
So, in actuality, several religious artifacts and symbols are not banned, they may simply pose security threats, which is why they're limited in certain situations.
Now for my personal opinion, I see no problem with religious aspects being implemented in schools, as long as it doesn't breach simple security concerns.