Tonight I was contacted by another motorcyclist that experienced a similar front tire valve stem failure at highway speeds. In talking with him, it appears that there have been more than just a couple of these failures and I sure would hate to see someone get seriously injured.
I went ahead and made a complaint at NHTSA, just to be on the safe side. Again, I really like the system, but metal valve stems should be required. I happened to see that Amazon.com was also selling the system and sure enough there was one review - and he mentions the rubber valve stem problem.
So, if you care to spend about 10 or 15 minutes, you can
File a Safety Complaint - NHTSA
Note for equipment information they want the make and model - I selected UNKNOWN for both and for Components I selected EQUIPMENT