For that company, open sourcing it would be a good learning experience as to the value of making at least the firmware and schematics available. I very much hesitate to purchase devices that I can't at least repair when the need arises. Conversely, I'm much more drawn to devices that can be hacked (in the true sense of the word) as well as repaired. Even if I don't have the time to do the hacking myself, there's intangible value to the possibility of doing so at any time. And it's fun seeing what others are able to accomplish. That's what open source is really about, not blantantly replicating designs for profit.
So, yes, at least make the firmware and schematics available. I'd also be interested in the rest of what goes on with an open hardware product (i.e., the process of bringing it to market, working with partners, keeping the product alive and fresh despite inevitable mass copying, etc.).