I don't understand. Is this really a thing? I'm from the UK and never heard such a thing.
Is this common in US?
What are they looking for? Do they just pick someone randomly, login to the laptop and check emails and stuff?
Same for devices - they have you unlock the device, then take it away, plug it into a PC/whatever, which sucks down a complete image of the device. Then they give it back, if they feel like it.
Obviously, if they do this with your email & facebook, they're also sucking in all your connections - your social graph: everyone you've ever emailed or has emailed you, everyone you're connected to on facebook.