One unmanned spacecraft (maybe the Voyager) contained a small optical window made out of pure diamond.
The manufacturer of the spacecraft had to obtain a federal export license and pay a tax on the diamond because it was being "exported" from the United States.
I believe you. That's why I hope Rutans tell the government to piss-off; this kind of meddling has got to stop, and the only way it will is if somebody with the reputation and balls of a Rutan, a Lindbergh, a Columbus, stands up and says "I'm mad as Hell, and I'm not going to take it any more." Trying to prosecute the Rutans for not getting a "Mother, may I" after they return from a successful sub-orbital flight that costs a tenth of what the Space shuttle costs to fly would be the biggest PR disaster the FEDS have seen since the Viet Nam War.