I saw on the Air Canada website this statement:

US Transportation Security Administration has issued the following information to passengers arriving into the United States and connecting to other flights or continuing on the same flight.

For your security, the TSA is screening all checked baggage. In some cases, screeners will have to open your baggage as part of the screening process. If your bag is unlocked, then TSA will simply open and screen the bag. However, if the bag is locked and TSA needs to open your bag, the locks may have to be broken.

You may keep your bag locked if you choose, however, passengers who elect to lock their checked baggage must do so with the understanding that this process may result in damage to locks and/or baggage delays.

TSA and your airline are not liable for damage to locks resulting from this.

Frances Toronto, Canada