"French Cops Foil Catholofascist Terror Plot"
Which is more superstitious, the belief that Lourdes water can cure the sick or the belief that it can bring down a plane?
It's quite a good question. And this isn't even one of those dumb rules that makes people feel more secure, everyone but the most unthinking among us knows that flights are in no danger from liquids (binary liquid explosives as plausible methods for bringing down planes was debunked long ago).
But all the effort detracts from the search for legitimate threats. But then again, the TSA has never been particularly good at finding bombs, but they're really good at confiscating nail-clippers.
I, for one, feel much safer.