Export restrictions have been in place for a very long time.
Another relatively well-known distributor that got bitten is McMaster-Carr, a mechanical parts supplier (with a very nice web design - http://mcmaster.com/).
After shipping something to a location they shouldn't have, they were penalized in 2003 and they no longer ship outside the US. Which is a damn shame, because they have a great catalogue of stuff that's very easy to navigate.