Luckily, the game isn't sold bundled with MotionPlus in the States (it is in Europe, but that's what those suckers get for living in Europe), so if you're still interested in a decent tennis game without the added "work" of MotionPlus, that's always an option.
ENGADGET: Wii MotionPlus review: it works, but so far the games aren't worth the fuss