I don't even understand why you bring this up.  The two guitars do not need to have the same physical interface in order for both of them to be supported in the game.  Of course I don't expect Harmonix to junk out their guitars and make new ones, that's retarded.

@windbane, I find it amusing that you think that owners of a console that supports WiFi out of the box and remains connected to the Internet even while turned off should not expect online features in their games.

Patents don't have to be protected.  Patents are a paid-for monopoly on a technology/invention/business method, where if someone infringes you have the choice to prosecute or not, but regardless of whether you do you still hold the patent and can prosecute at any time (barring other contractual obligations such as licensing, etc.) I can patent something new tomorrow, and sit on it until the day before it expires while people infringe on it all over the place, and I am still able to sue for past infringement.

You're thinking trademarks.  If you don't protect your trademark you lose it.  Copyright and Patent are guaranteed even if you don't protect it.  It's just, if you don't sue you don't make money (assuming people aren't licensing it at least).

That said, you cannot protect how people use your technology through patents no matter what.  If I make a widget that I want people to use with the Wii, and people want to use it with their computers, that's not covered by patent law.  Depending on what my widget does, it *may* be covered by copyright law, but it is explicitly not covered by patent law (IANAL, TINLA).