On Wed, 13 Feb 2008 09:46:58 -0700, Bill Jeffrey
wrote:

At least some of these things are not magnetic at all, and I think that
applies to the one you cut open.

No, he's correct. The magnetic thingee is not an RFID just anti theft.
There are three very thin pieces of metal in there. Two of the strips
appear to be mu metal (I'm guessing) and another magnetic iron.

These are "electronic article surveillance" tags, or EAS

I had the operation backwards. From what I'm reading the tag can be
deactivated with a magnet and activated with a degaussing device.

http://electronics.howstuffworks.com...ng-device4.htm
The Electromagnetic (EM) system, which is dominant in Europe, is used
by many retail chain stores, supermarkets and libraries around the
world. In this technology, a magnetic, iron-containing strip with an
adhesive layer is attached to the merchandise. This strip is not
removed at checkout -- it's simply deactivated by a scanner that uses
a specific highly intense magnetic field. (One of the advantages of
the EM strip is that it can be re-activated and used at a low cost.)
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