Whitelists are scary for governments. I've asked TSA for whitelisting of DOT-approved materials to be carried onto airplanes (Ferrofluids are inert, but they su

Whitelists are scary for governments. I've asked TSA for whitelisting of DOT-approved materials to be carried onto airplanes (Ferrofluids are inert, but they sure look funny in an X-ray scanner), and they were clear that the ranking TSA officer had final say on all allowed materials at any time. I shipped by mail. If something _must_ be allowed, then the government is in a tricky spot when someone constructs something that they'd rather not allow entirely from allowed parts. TL;DR: Blacklists are scary, whitelists are empowering.