I'm slightly baffled by the Intel-provided ipw3945d regulatory daemon I
have running for my Intel 3945ABG wireless card under Linux. My laptop
is American and I found I couldn't connect to a Japanese 802.11a
network.

As far as I can tell it's actually limiting which channels the card will
talk on at all. For instance, in the 5.2GHz band, it will listen on
channels 36, 40, 44, 48, etc. but not 34, 38, 42, 44 or whatever.

What I want to confirm is, I can understand wifi NIC vendors wanting to
restrict what frequencies it will broadcast on, because of FCC
requirements, but do they normally even restrict on what frequencies the
card will respond to an access point's beacon on? It won't even listen
and broadcast even if the surrounding access points are obviously
operating in a different regulatory environment?

It just seems so silly when people obviously travel with their laptops
and whatnot. What do 'b/g' people do when travelling to Israel with a
Spanish laptop? What do 'a' people do when travelling to Japan with an
American laptop? Buy a NIC in each country? (Is the regulatory daemon
responding to some region code embedded in the NIC? It says something
about 'detected geography' but I very much doubt it can tell where my
laptop computer actually is.)

-- Mark