I recently took a domestic flight from the Oakland, CA airport. While waiting for the airplane, I spent some time observing the security measures at the X-ray machine. As most readers probably know, laptops are often subject to manual scrutiny. From my non-representative sample, about four out of five tote bags clearly containing laptops will be manually searched. Typically, the attendant requires that the laptop is powered up. In none of the 20+ manual searches I witnessed did the security personnel wait past the RAM check before clearing the passenger. I could not help but contemplate how much of the insides of the laptop could be replaced while still obtaining an identical display. Then came the big one: A man wearing a beer truck driver uniform approached the checkpoint. On his hand truck were two kegs of beer. For those unfamiliar with such objects, a keg of beer is a cylindrical stainless steel container, about 1.5 feet tall with about 1 foot diameter. I was wondering what the procedure for handling these rather large steel containers would be. Would they be X-rayed? How much shielding would the steel provide for the contents? Much to my surprise, the man did not approach the X-ray machine. Instead, he went straight for the "exit only" walkway. The guard posted there to make sure that nobody would enter through the exit gave the fellow only a cursory glance as he entered the "secure" area unchallenged. I was flabbergasted. They let a man with two *large steel containers* enter unchecked? No asking for ID, no X-ray? I struck up a conversation with the beer truck driver. I asked him why the kegs did not get X-rayed. He looked at me with an expression of utter lack of understanding and answered: "They are too heavy to be put on the [conveyor] belt." Right... We wouldn't want to have these 50 pound steel barrels jam the X-ray machine. -- Lucky Green <mailto:shamrock@netcom.com> PGP encrypted mail preferred Make your mark in the history of mathematics. Use the spare cycles of your PC/PPC/UNIX box to help find a new prime. http://www.mersenne.org/prime.htm