Yes, Nikon does add some obscurity by encrypting the WB setting. However, the original poster made it sound as if the entire file was being encrypted, which is a very different thing.

At best, encrypting the WB setting makes things mildly more annoying for if you're working with a 3rd party RAW converter. The reason I say this is because I know a number of photographers who don't use WB when shooting and instead handle that in post-production. Others may set the WB simply so that the JPEG preview looks reasonably close to what the final shot would look like.

That aside, let's look at what the WB setting actually does. It adjusts the colour based on the colour temperature of the lighting in order to remove any colour cast. A lot of people obsess over using custom WB settings but it's not really that big a deal. For outdoor shooting you probably want to maintain the character of the lighting so you don't want a custom WB. For instance, if you're shooting just around sunrise or sunset you want that nice yellow-orange light. Setting a custom WB will eliminate that look. Another example would be a message I saw on one of the photo lists I'm on, the poster was complaining that his snow shots didn't have the slight blue colour he wanted to make things look cold. The problem was he was using a custom white balance that was balancing the snow to be pure white instead of slightly blue. Simply using the "daylight" WB would have been the best option.

For indoor shooting you're most likely dealing with either tungsten or flourescent lighting. Both of these can usually be adjust for with standard WB settings.

So what's left? The main usefulness for custom WB settings is when you're working in mixed lighting. Say an indoor shot where you have tungsten and flourescent lighting as well as daylight coming in from windows. That's a tricky lighting situation. That's when you are going to want to set a custom WB. However, you can just as easily take a shot of your grey card (which you should be using to get an accurate WB setting in the first place). If you really want to get accurate colour you should shoot a frame of a colour chart (such as a Macbeth colour chart) and adjust off of that. In your RAW converter you can then use that shot to set your WB for the whole set of shots.

As for the DMCA, it sounds like it would set Nikon up to be in a position to sue if another company decrypts their WB information without permission but you should still be able to read the image data itself. I think you'd create some nasty legal issues for yourself if you were to prevent the legitimate copyright holder from accessing their images.

That said, I do agree that it'd be nice to see an open standard in use. My main question is how well a format would be able to support all current camera models (which store various amounts of information in the RAW file aside from teh sensor data) and also scale with future models? I don't know enough about the DNG format to say how it would work with this. My guess would be that it's like the TIFF format where you can freely add tags to the format. If that's the case then you could still run into the same problem with things like WB settings (or any other piece of information) even without encrypting them because different manufacturers could decide to record the information in different ways.