I understand that we need to be careful take precautions and all that but come-on we closed down an entire terminal because somebody shipped a computer monitor? If a dog smells explosives, fine, shut down the airport, but just because a monitor releases some radiation (which it's supposed to do) doesn't mean we need to shut down an entire terminal while we wait for an all clear.
This is the first time I've ever heard of a computer monitor emitting radiation when it's turned off (I'm assuming a monitor inside luggage would have no power source). CRT's emit some X-rays due to high-voltage vacuum tubes but only when they are on, and who uses CRT's anymore ?
I'd be curious if anyone can explain why an unpowered monitor or a flat-screen monitor would emit ionizing radiation. A Google search for "computer monitor radiation" turned up no technically useful information on the first couple of screens.
I am quite confident that bombardment with X-rays of several keV has no effect on the natural background radiation of lead or any other material. Such effects require nuclear interactions with activation energies in the MeV range or greater.
I tried packing one of my monitors inside checked luggage back when I was flying to/from college a lot. It didn't fit, and in retrospect I guess that was a good thing -- although this was 4-6 years ago when security personnel were slightly less insane.