Canadian law seems really grey and, frankly, a bit confusing. I'd love to find a set of definitive guidelines regarding what's okay and what's not, but I doubt such a beast exists.

Outside of those items specifically prohibited, my understanding is that anything becomes a weapon based on intention (and of course use). So if the police ask what your knife is for and you say self defence, its a weapon regardless of its physical attributes. It is legal to carry tools, not weapons.

Concealment is a bit confusing; concealment would only seem to be a crime if it was found that your knife was a weapon. Therefore, as a general rule, most recommendations I've seen are to not conceal your knife just in case (e.g. have the pocket-clip showing).

That said, my hometown has passed a bylaw that says a knife cannot be visible in a public place which seems to be a bit of a catch 22. That said, I'd lean more towards ensuring I was completely above board criminally rather than worrying too much about Bylaw.