How can a lap top that was already screened be a security threat? It was screened, the owner stepped away, and came back. I’m sure it would end up in the lost and found until the owner who had a senior moment retrieved it. If it was abandoned before the x-ray area, yes, that could be a problem. But, if had already been screened, then it was not a threat. I don’t see the problem, other than someone could have had their lap top stolen.
Maybe the same way that cell phones can be? I see a problem with leaving such an expensive piece of equipment around, considering I can't afford to own one. They'd be prying the damn thing from my cold, dead fingers, lolololol!