Missed this one

http://www.cbc.ca/world/story/2007/03/02/swissinvade.html

Behold the power of the Swiss army and their glorious knives!

Wait, never mind, they accidentally wandered into a country with no military of any kind. That's how invasions are done people. Crush them while they're weak.. wait, they went back home you say? Hmm. So I guess they're just silly.

But Vaduz is home to a more secure and discrete banking system than the Swiss have. Luxemborg is where the world bank is, so virtually everyone over there has sophisicated and secure bank systems, Switzerland just happens not to be prone to invasion by hostile Huns or Napoleonic conquests. I'm guessing they just didn't like the competition and its not like the Swiss could accidentally invade the Cayman Islands.