The # character is silent, variable, and sometimes even invisible
As far as trademarks go, nothing is silent. Anything that is visible to the human eye can either constitute part of a, or differentiate between two or more, trademark(s). I don't dispute Gamesnet's interpretation, if you've quoted their ruling then that's that. What I am saying is that there is no actual law that supports what they are saying. If someone wanted to go to a network and open/register/run a room called #mIRC then there is nothing that anyone else (apart from network staff) that can do anything about it.
We don't live by Common Law
Then you have no real idea what the Common Law actually is. Common Law covers not only any behaviour of a person or entity acceptable to society in general that is not covered by a statute, it also applies to interpretation of statute by a court where the statute either has no precedence or contains open-ended clauses, commonly referred to as loop-holes. This is in addtion to any historic meaning, interpretation, implementation of Common Law pertaining to the unwritten consititution of Great Britain or King John or the Duke of Normandy, etc etc etc.
