I wonder sometimes if policies like these are monumental cases of the XY Problem in action.
For example, the government/border agency decides that travellers must give up their phones and account passwords. In fact, other governments/agencies see this as leading by example and tag along for the ride.
The justification we hear is 'national security' and, since the first thing we were aware of was the solution itself, we treat it as viable without much scrutiny and proceed to fill in the blanks about what 'national security' means to us: is it terrorism? drug trafficking? illegal immigration? some other hot button topic?
It begs the question and the frustrating thing is; we know the real answer: governments just love authority and surveillance. Yet still, how about some other questions...
What is a better solution to preventing terrorists from hijacking your plane? It would make sense to address the circumstances that actively encourage terrorism, no? That's foreign policy.
Drugs crossing the border? How about checking for the physical presence of them as opposed to forcing people to incriminate themselves for recreational drug usage?
Illegal immigration? That means a lot of things to a lot of people and, if my experience in Canada is anywhere near representative, it might actually be more successful if it wasn't so strict.
In no case does getting unrestricted access to your social media accounts, your collection of nude selfies, entire history of messages going back years, etc. actually aim to tackle the real problems. All the reasoning does is save the government the job of justifying its pathological obsession with your private life.