On the other side of the fence, also Canadian, my debit card has been compromised many times. Bank always shuts it down immediately and lets me know, then returns the money. I have never been asked to prove anything. Usually they ask me to double check and see if any other charges than the ones they caught were fraudulent.

This has been as simple as someone using a copy of my card to buy candy and video games, something I could have done but didn't in this case.

Really impressed with the services of my banks when it's come to debit fraud.