> A CBSA officer will start with some questions before examining your personal digital device. To examine the device, the officer will first ask for the password. If the device is password-protected, they will write your password on a piece of paper. You are obligated to provide your password when asked.
> Note Failure to grant access to your personal digital device may result in the detention of that device under section 101 of the Customs Act, or seizure of the device under subsection 140 (1) of the Immigration and Refugee Protection Act or under section 110 of the Customs Act.
Well guess we’re not going to Canada again.
It also never mentions them destroying the written down password.
> Electronic devices held for forensic examination under section 186 of the Customs Act will be retained for no longer than 14 days, provided there is no content on any device retained which renders the device subject to seizure under Customs-related laws. If any device is subject to seizure, the examination of any associated retained devices may take longer than 14 days.
It's a border crossing, required unlocking of devices is common practice including especially by the US. National sovereignty is supreme and countries have the right to implement whatever procedures they deem necessary before permitting entry.
Unlocking of devices is distinctly different than “write your password on a slip of paper”. Even if they shred the paper, the room for sure has CCTV video recordings so they’ll have a copy there as well.
Good thing all of us here are following (and extolling) the advice to never reuse passwords, espcially when ones device is in an evidence locker and subject to controlled access by authorized personnel
* https://www.cbsa-asfc.gc.ca/travel-voyage/edd-ean-eng.html