[elementalest]

Yeah, there was no mention of locking out other HMD:

> In return we ask that your device leveraging our technology works with our platform. And mostly that is it. We won't ask that it only works on our platform, we won't stop you from targeting other industries. This gives both you and your users freedom of choice and security that isn't dependant on either party's future decisions.

As long as the HMD supports the steamVR platform requirements, it can play steam/valve games.