I cannot imagine karaoke being that popular.
Rather than debate this if you have and Android phone or Apple iPhone for that matter go to to the App Store and search for "karaoke", you will find that there are quite a few apps (I counted 250 on Android) dealing with that. Now just for fun why don't you "tap" on an app (don't install unless you want too) and see how many downloads of that app has had.
Basically you are going to see 100's of thousands and even millions of downloads per app so just because you can't see karaoke being that popular I think 10's of millions would disagree with you.
Who would buy/download karaoke for personal use?
If you like watching Japanese Anime you may find the introduction and ending song if there is one set-up with "karaoke" and people do buy the dubbed/subbed anime.
why is this a target for the police when there are plenty of other, and larger, trackers out there? Nothing in this story makes any sense.
It looks like the big corporations want their pound of flesh and they don't care were they get it.
On a side note, do you know it is actually illegal to sing "Happy Birthday" in a public place without paying royalties.to the copyright owners. Now IMHO that makes no sense but the law is definitely on their side.