TSA rules on liquids

Begin forwarded message:

From: "Steven M. Bellovin" <[email protected]>
Date: October 31, 2006 8:00:10 AM EST
To: [email protected]
Subject: TSA rules on liquids

For IP, if you wish.

Today's Wall Street Journal has an article on the liquid carry-on rules
promulgated by TSA.  Much of it is familiar to readers of this list,
including the screeners who don't really understand the rules.  One  
thing
that I haven't seen mentioned much before is that they're really  
concerned
about containers, not just liquids:

	To travelers, some of the regulations are bewildering. You can
	buy a filled water bottle at an airport shop inside security, for
	example, but you can't carry your own empty water bottle through
	security and fill it at a water fountain inside security. Mr.
	Hawley says there's a classified security reason for that related
	to the characteristics of liquid explosives. In addition, X-ray
	machines can detect containers, just not what's inside. So getting
	all containers out of carry-on bags speeds up security screening.

	"As stupid as we may look, we didn't miss that one," Mr. Hawley
	said.

	...

	Mr. Hawley said there is method in the madness of requiring
	everything to be in a bag and strictly limiting the size of
	containers, not the volume of liquid or gel. Containers larger
	than three ounces could pose a threat -- a place to mix enough
	liquid explosives to create a bomb. "It's not the ounces. It's the
	container we're after," he said.

Oh yes -- Continental and Southwest have quart-sized bags at their  
ticket
counters; just ask.

		--Steven M. Bellovin, http://www.cs.columbia.edu/~smb