I came across this article in my daily blog visits:

En route from San Jose to Phoenix, I was told by a Transportation Security Agency (TSA) screener about a ban on lighters (cough) starting April 14th, but the book allowance has been cut from 4 to 2. I had been tagged for a pat-down, a perfectly reasonable thing considering whatsinmybag. The agent was reasonable and amicable and I knew the drill. When he pulled a cigarette lighter out of my bag he mentioned the forthcoming ban, how you could carry four packs of matches and the whole idea was to prevent quickly lighting explosives (like that idiot with evil shoes). When he pulled out two books he mentioned that right now you can only have four books and on the 14th you can only have two. He didn't have any explanation for this, and I can't even fathom the purpose.

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I was pondering what the real physical security issue was. If it was a question of weight (some of those hardware books can make wicked weapons when tossed) or size (perhaps hiding something?) then I could understand but it's done as a generalized policy (2 books instead of 4).

So does anyone have an idea or guess as to why this would be limited this way?