The bomb detectors (if it passed through any) were more likely trying to detect actual chemical signatures of explosives rather than just a bunch of wires that might be a detonator. So something like this would pass fine, as it should.

Because outside of the US people are not paranoid.

There are countries in the world where this would rightly trigger a bomb scare. It's nothing to do with paranoia - in some places mail bombs are a reality.

Which places would that be?

Here is one example: http://en.wikipedia.org/wiki/Miles_Cooper_letter_bomb_campai...

Sadly England seems to be.

http://www.bbc.co.uk/news/uk-england-manchester-23727511

That isn't paranoia.

A rather large bomb was set off by the IRA in 1996 within walking distance of the sorting office in the article. There have been multiple bombs planted recently in NI itself.

NI?

Northern Ireland.

People send battery laden electronics through the mail all the time. It's about all Sparkfun ever ships. Doesn't seem to be a problem.

Actually,'bout that: The USPS has banned the mailing of batteries, not because they're worried someone will disguise a bomb as one, but because they have a habit exploding in atmospheric changes.

You can certainly mail batteries, just with some restrictions.

http://pe.usps.com/text/pub52/pub52c3_024.htm

The picture on hackaday was of the inside of the box. Ruben's site shows more pictures of how the box looked closed.

http://www.rubenvandervleuten.com/AtoB.html

Because it's from Denmark.

Actually how is the legal situation on this? If they go all bomb scare crazy over this is it my fault as the sender even so it is not even remotely reassembling a bomb layout? Is there a ban on mailing home made electronics? Or do I need to put a sticker on ATTENTION, THIS IS NOT, I REPEAT, NOT A BOMB!

Why would they even know what's in the package? It shouldn't be going through any kind of xray machine.

Maybe they scan heavy packages only. A camera + controller + memory could go through a 'normal' path

Because as long as the package isn't making weird noises no one cares what's in it.

Because it's not a bomb?