Since last August’s discovery of a terrorist attempt to use liquid explosives on US-bound airplanes, air passengers have been subject to a TSA ban of liquids and gels.  Such ban was subsequently modified to permit small amounts (3 ounces or less) carried openly in zippered plastic bags.
The ban includes the popular souvenir snow globes seen in shops wherever one would find tourists.

NYT Link

“Snow globes, regardless of size of amount of liquid inside, even with documentation, are prohibited in your carry-on.”

Judging from the lines one regularly sees at airport security checkpoints, I suppose that a total ban makes more sense than weighing each individual globe for the 3 ounce compliance.  One can only imagine the outbursts of young children upon the loss of their prized possessions.

But attempting to put a lid on terrorism via bag searches is seen by at least some private security experts as a futile pursuit.  As to the foiled liquid explosive plot:

But the plot seems to have been thwarted before the bad guys reached the airport, because of intelligence and police work, not a focus on rummaging through carry-on bags for bottles of shampoo.

“If you look at the London plot, assuming it was a plot, no security measure then in place would have caught it at an airport,” said Bruce Schneier, an authority on security technology and the author of the book “Beyond Fear.”  …

He added, “Screeners are so busy looking for liquids that they’ve missed decoy bombs in tests. We’ve defined success so weirdly. When T.S.A. takes away some frozen tomato sauce from grandmom because it might become a liquid, they think of it as a success. But that’s a failure. It’s a false alarm.”

The TSA has thoughtfully provided various other directives, all in the intended interest of safety.  The agency has even gone so far as to provide guidelines to the handling of trained monkeys sometimes used by the physically challenged, much as dogs are used by the sight-impaired.

One can only imagine the mood of the author of this passage.

“When the handler and the monkey go through the W.T.M.D. and the W.T.M.D. alarms, both the handler and the monkey must undergo additional screening.” The rules add that security officers “have been trained not to touch the monkey during the screening process” and that “the inspection process may require that the handler take off the monkey’s diaper as part of the visual inspection.”

Mr.Schneier again:

He added, “We spent billions on security to make the bad guys make minor modifications in their tactics. Focusing on the tactics only works if you happen to guess correctly.”

More TSA here.