Not April Fools: New Zealand Proposing Software Patent Ban
arstechnica.com
arstechnica.com
If your talking about writing your own SAS competitor which infringes on SAS patents, thats one thing. But your comment seems to indicate your talking about software piracy, which does not seem to be what this NZ proposal is about.
It's not a question of doing business in the US, it's a question of the US' ability to access your companies assets.
Of course if you're an American citizen operating a sole-trader in Europe it is you violating the patent, no company officially exists. You would be fully liable in the US for everything from your house to the current pair of underwear you have on. If a court decided you were liable, you're screwed. If you're incorporated in a foreign country, you'd never be liable and the courts would never be able to argue jurisdiction.