In AES
wrote:

Is this in fact in the rules, in the U.S. or the EU?

In the US you need to keep this in mind:

To ensure traveler's security, transportation security
officers (TSOs) may determine that an item not on the
prohibited items chart is prohibited. In addition, the TSO
may also determine that an item on the permitted chart is
dangerous and therefore may not be brought through the
security checkpoint.

http://www.tsa.gov/assets/pdf/Prohib...ly_3-16-07.pdf

--
Bert Hyman St. Paul, MN