Not really...that's a bit like saying that a car owner should go to jail instead of the thief who stole the car after the keys were accidently left inside of it...
It seems the best initial defence isn't to say someone else did it, but to instead deny downloading the material... The fact that you have unsecured wireless and even the fact that you don't have a Wii is probably best kept for later once you've wasted enough of their own precious time
