This makes sense, right? You can bring a bagel with lox and cream cheese through security, but cream cheese by itself is banned. From Freakonomics:

My niece was back home in Milwaukee visiting family and stocked up on bagels, lox, and cream cheese to take home to Kentucky (forget for our purposes the madness of thinking that Milwaukee has a clue about bagels etc. – she is right – at least they have heard of them in contrast to KY).  Anyways, the wonderful folk at TSA said she could take the bagels on board and the lox, but the cream cheese was out! But being proud civil servants – an oxymoron if ever there was one — they agreed that it would be okay, and she could bring it on board, if the cream cheese was spread on the bagels. Please write this down for future reference.

Useful to know if I want to bring lox and cream cheese to Kentucky.