Canada is successful 38% of the time when checking electronics. Common scenarios are seeing text messages showing someone has accepted a new job and will be working while on a visa waiver/tourist stay, or planning to get married while on a work visa.
But they don't stop people coming into the country or seizing their property. They are temporarily withholding the devices and copy the data. That's why you use full disk encryption - is they want to copy and store pseudo random data, let them.
