I am sure Canada law differs from the U.S. My sister had a safe deposit box. She put me down as co-owner and gave me a key. When she died I was able to go into the bank on the day of her death and open the box and take out the money she had stashed in there. Her daughter was ripping mad. I knew about the box and she didn't. She insinuated that I kept some of the cash and didn't hand over all of it to her. I haven't spoken to her since the funeral. For all she knew that could have been my money and not her mother's. Her bank account was frozen. All she received each month was her SS check. When she received it each month, she took out all but $5 and placed most of it in the box. She knew about the frozen accounts on death. When she needed cash, she would go into the bank and take some cash out of her box. To pay her bills, she would give me the cash, I would deposit it in my own account and write out the checks for her.
If her kids knew about that box, I honestly believe her life would have been in danger. There was a lot of skullduggery going on between the two of us that her kids had no hint of. And still don't. By the time of her death, there was over $10,000.00 in that box. A little this month, a little the next month. All gift monies went into the box. Over the years it added up. It paid for her funeral.