[ghkbrew]

> Validate the integrity of the device from looking at the screen?

Essentially, yeah. If you can't turn it on, it could be an IED disguised as a cellphone. (Or so the TSA seems to think)

Of course it's all just pointless security theater. I keep waiting for the general public to realize that these sorts of measures are useless wastes of money and demand they stop. I fear I'll have a long wait.

(Edit: TSA not NTSB)

[amatix]

Or if you're even a wee bit sophisticated, get a smaller battery pack that'll last for 15 minutes and pack your explosives into the remaining 90% of battery space? How does the TSA not think of these blindingly obvious things?

[mikeash]

"It is difficult to get a man to understand something, when his salary depends upon his not understanding it!"

Nobody is going to put themselves out of a job by saying, "Ubiquitous security screening doesn't work, as every countermeasure we come up with has obvious counter-countermeasures. Thus, we should shrink this agency by a factor of five and refocus our efforts in other areas."

But they can't just ignore threats either, because that gets you hauled in front of Congress the next time something happens. Thus, they ride a line of carrying out countermeasures that don't really help, but which are enough so that they can go to Congress and say that they did everything they could.