Unlike many people on this list who say that they have "not flown since September 11th" I have managed to attain "Plutonium" status in my frequent flyer program since 9/11. To say I spend lots of time in the air would be an understatement. I know pilots who fly less.
The TSA publishes a really nice list of the things that are "permitted", and this list is readily available at:
http://www.tsa.gov/public/interapp/editorial/editorial_1012.xmlAlso on that page is the following statement:
"Prohibited items are weapons, explosives, incendiaries, and include items that are seemingly harmless but may be used as weapons - the so-called "dual use" items. You may not bring these items to security checkpoints without authorization."
The operative words are "seemingly harmless" and the fact is that ANYTHING - a CD, a laptop, ANYTHING is a "dual use" item if the TSA decides it is.
On pages 3-4 of the official list, as updated 16 may 2005, is a section that discusses "Self Defense" items, all of which are not permitted.
Thus, while the device in question may not be RECOGNIZED as a self defense weapon by name, it is most clearly NOT on on the "Permitted" list, and, per the "dual use" option, all that is not permitted is potentially prohibited.
Thus far the only "TSA" approval that exists is for locks with an override key that the TSA has. While the company making the device in question will replace it if confiscated, I wonder if they will also accept liability for any legal costs that come from an arrest as a result of the claims made that the "TSA approved" this device. Certainly one with a good lawyer could make this case and win it.