Strictly for comparison... Section 8 of the Canadian Charter of Rights and Freedoms: Everyone has the right to be secure against unreasonable search or seizure.

And here's the section of the Aeronautics Act that gives us the authority to open bags without the owner being present (although by policy we don't do this except in exceptional circumstances):
Search of goods
(7) No person who, having been required by a screening officer to permit an authorized search of goods that the person intends to have transported on an aircraft, refuses to permit the search to be carried out shall place or attempt to place the goods or cause the goods to be placed on board the aircraft.

Unaccompanied goods
(8) Where goods are received at an aerodrome for transport on an aircraft and are not accompanied by a person who may give the permission referred to in subsection (7), a screening officer may carry out an authorized search of the goods and, in carrying out that search, may use such force as may reasonably be necessary to gain access to the goods.