On top of that, if screeners can't tell the difference between legitimate devices and bombs in a carryon, why would they be able to do any better for checked ba

On top of that, if screeners can't tell the difference between legitimate devices and bombs in a carryon, why would they be able to do any better for checked bags? Bombs in the cargo hold are still bombs. One explanation I'd heard was that checked bag screening areas are more secure, while for carryons a rogue gate employee could wave through a suspicious laptop without any further backup checks... or even a rogue food-service employee could smuggle something in and hand it off to a passenger. But that could happen with any 'container object,' not just laptops. And it's hard to square that a ban expanding to major European airports.