It probably is a reasonable test for the short term, but now the terrorists know they can't completely gut a laptop and then get it through security with the excuse that the battery is flat, so they'll have to make it keep working and only be half-gutted, if the intelligence-led tests keept up with that sort of development every few months, fair enough, but in general the "something" becomes a long term measure even if it's just to make people feel safe the same way as the bottled water and toothpaste rules have.