I had to sign some legal papers when I sold a domain a few months ago. One thing they wanted me to sign was a thing about how I was not allowed to register names with the same name in it. And if I did, then I would have to give it/them to them. I signed it because the name is something I wouldn't register again anyways, and if something did come along, I could just register it under someone else, like someone in my family
They didn't say anything about other names though. I wouldn't sign something like that. It could affect to many potential domains that way.
RMF