Problems buying Nikon parts?

I just bought a new Nikon, but I heard that buying the parts are beginning to get difficult. Why is this?

http://peachtreecamerarepair.com/_pcr/nikon-not-selling-parts-petition-usa/

Nikon tightly controls the parts distribution and only sells to Nikon repair centers. However, you can often buy new OEM parts from eBay which are direct imported. I bought a replacement rubber thumb grip for my D90 from eBay and it fit perfectly.

You have to be careful though on eBay as many of the repair parts are used - from people parting out cameras. But a couple of eBay sellers do sell new parts.