FUBAR

Alright I have a question about the drug dogs. I go to high school in Canada, Ontario to be precise, and I was wondering what the laws were on the drugs dogs. We had drug dogs go through our school about a month ago and i was wondering what they are aloud to search? They walk by all the lockers and then take them into randomly chosen classes. My english class was one of them. Luckily I didn't have any ganja on me. The cops took us out of the room and then had the dogs search the room with all our stuff in there, but they never had the dog go by us(the students) in the hall. Is this because they arent aloud to have the dogs around the students? I believe that I could have gotten away with having weed in my pocket, but I deffinately would have been caught if it were anywhere else. Are there any policies about what the dogs are aloud to do, or is it different for every school board? This would be very helpful, so I can keep weed in my pockets without the fear of a dog coming in.