Events like the G20 attract many photographers. Photographers with especially large cameras, taking many pictures, can attract attention from police or security– and there’s a lot of that going around. If you are a protester or simply an interested party it’s important to know your rights and responsibilities when it comes to being a photographer.
An entry in the Globe and Mail’s G20 Blog informs us that police cannot ask you to delete photographs, or threaten you if you refuse to (well, they can, they just can’t legally). They can ask you questions.
Your right to photograph everything, however, does not extend to private property. If you are on private or semi-private (e.g. a mall, private building plaza) property, security guards and police can ask you to stop photographing and/or leave. You should comply or face trespassing charges.
Complete Canadian photography-related law, from AmbientLight.ca (linked to below the Globe and Mail post). A very helpful site, with advice concerning what to do if you are approached. If you’re a protester or someone who plans on hanging around them to get dramatic photographs, you might also want to familiarize yourself with trespassing law, which is included.