Weil,
I also thought that the copyright issue is the main aspect of this topic. I am not expert in copyright and believe that it is not easy at all to prove a right over a design - probably one of the things which one would look at is how much ´unusual´ is the design and ´unlikely´ to arrive at by any other means than copying. We should also remember that there is a certain degree of copying which we all do.
When I started to work for the office in Sydney I signed on a document that anything I do on behalf of the office belongs to the office which can enjoy the credit for it and has the right to amend it in the future.
Cheers,
Mati
