You know how Nintendo has certain downloads that are only available if you own a special code? You need to buy the WiiSpeak microphone before you can download the free WiiSpeak channel.
Perhaps the WiiMotion+ accessory comes with a code which lets you download a free or cheap WiiWare game. That way only people who own the accessory can download or buy it.
Or they can make a game that doesn't NEED WiiMotion+ to work, but is much much better with WiiMotion+. That's how all the Balance Board ski and snowboard games work. They can work without the Balance Board.
Also, WiiMotion+ is coming out on a Friday in Europe, which is also their weekly WiiWare release day.
I just refuse to believe that Nintendo will sell this for $20 before a single game uses it. That's unheard of. It needs a launch title. We'll get at least one. Something to warm us up for Wii Sports Resort. Something to get reviewers tingling for a month in advance.