I suspect it will make little difference. A sophisticated terrorist could probably allow for enough room inside a laptop for a Raspberry Pi, Gumstix or similar computer module to display a convincing BIOS/UEFI boot-up message, possibly followed some kind of shut-down error due to low battery or corrupt file system. I would seriously doubt if a TSA agent would know the difference between that and, say, a legitimate boot screen for every Linux distro out there.
Frankly, I'm not sure what the advantage is to this kind of screening. After all, the January 2011 bombing at Moscow's Domodedovo airport demonstrates how effective a suisidce bombing can be inside an airport. I would imagine that a bombing at crowded TSA chokepoints would be the exact kind of target terrorists are looking for.
I would imagine that when a bomb goes off, the entire airport goes into lockdown and all of the incoming planes are redirected to alternate airports. Repeat that bombing once or twice more on the same day and you have likely paralyzed that nation's airspace and related infrastructure for several days while they try to and figure out how to respond.