I haven't seen wall warts or small power supplies that were made anywhere else.
Good point. The danger sign is probably "cheaper than it seems possible", rather than "made in China."
Although "shipped direct to you from China, bypassing regulatory approval processes" is probably also a bad sign.
The Apple USB-supply cube is impressive engineering (much smaller than the LED supplies you linked), now widely (and sadly) "faked" with a much less worthy/safe circuit. Much of the recent publicy has surrounded fake Apple chargers. EEVblog #388 - Fake Apple USB Charger Teardown - YouTube
http://www.arcfn.com/2012/03/inside-cheap-phone-charger-and-why-you.html
(Real Apple or Amazon chargers aren't "inexpensive.")