I've met the umpteenth "open hardware" device on the web, whose creators deemed posting a bloody pdf with a circuit diagram enough to be "open". (And the C source code for the microcontroller firmware in Github, of course.)
I asked one where the Eagle or Kicad or gEDA files are, or maybe the Gerbers, and the reply was that "we don't want to publish those, because that's where the real intellectual property is, we worked a lot on those."
Now that's fine, but I seriously doubt these people should be calling themselves open hardware. In this spirit, HP, Agilent and pretty much the ENTIRE industry pre-1980s was "open hardware", because if you bought anything electronic, you got a circuit diagram with it.
It just ticks me off to no end. There should be something like GPL for hardware that describes what constitutes "open".
EDIT: Yes, I'm thinking "open source" rather than just "open". There IS a point of conforming to open standards, and sharing knowledge, while being closed source for one reason or another. That said, I'm convinced that most "maker" and hobbyist projects would benefit a great deal from being "open source" as well as "open".