1) That's a huge assumption. Especially given that he went to see Laura Poitras
2) Sure, but for that they didn't need to seize them, they could have copied them. I take it that Greenwald et al are smart enough to use an encrypted dead drop on the net rather than to hand-carry unencrypted bits with the keys in the head or the possession of the carrier.
From the government perspective I can see only bad stuff coming from this, it is a very clear abuse of the law, it will take a lot of tapdancing to explain this one away as a rogue employee.
I guess they estimated that there won't be many occasions where they'd have to explain that at all. When the Bolivian president's plane was already taken down, who's gonna react about the "ordinary Brazilian guy" kept on the customs?
Moreover, TSA already prepared the people to be numb about the inconveniences at the airports. It became hard to make news about that.
Of course I can't possibly know but I agree with @acqq I think the effect of surprise worked and it was all about that in order to grab the hard drive for current and past files and his contact list on his phone. I think that if he was really prepared and if he was expecting such a move he would have tried to avoid Heathrow.
2) Sure, but for that they didn't need to seize them, they could have copied them. I take it that Greenwald et al are smart enough to use an encrypted dead drop on the net rather than to hand-carry unencrypted bits with the keys in the head or the possession of the carrier.
From the government perspective I can see only bad stuff coming from this, it is a very clear abuse of the law, it will take a lot of tapdancing to explain this one away as a rogue employee.