Why would it matter at this point? That would be like a car wash being afraid of cleaning stolen cars. If there is an album on my computer, then I either downloaded it from a legitimate site (iTunes Store or Amazon), ripped it from my CDs or LPs, copied it illegally from a friend, or downloaded it illegally. No matter how the music got on my computer, if there is something wrong, then the damage has been done long ago and there is nothing they can do about it. (Actually, the music industry could do something about it: Sell a license for x$ per month that allows you to have any of their music on your computer, wherever it comes from, and play it. Just collect the money for the license, and leave the distribution to people).
But also, why would anyone think that there would be any music on my computer that I don't own? There are at least 100 CDs that I bought in the last twelve months alone.