It takes some observational skills but see 1. T3 Spammers; mp3 Bit-Rates Versus File Sizes & the reasons are here; Most Popular Songs R' Corrupt

I'm interested in these corrupted files, as I don't know if I've ever had them. Given, I don't download much (not more than 200 a year), and I naturally go for names that sound real (no underscores), and I avoid T3s because I have a hard time believing there could be that many T3s out there. And getting my file in a minute instead of 20 seconds is no problem anyway.

Did these natural avoidances keep me away from these corrupted files???

My guess is that you don't often download new tunes that are hits. I notice that it's the new tunes that have current airplay that have the most issues. I think the labels are putting out the junk files to discourage downloading. I can't verify this, but it makes sense to me.
Funny thing is, these labels are trying to sue the little guys for downloading, but they are often doing nasty stuff themselves. For instance, Sony (one of the big labels) recently got busted for Payola. That is, they were paying off the radio stations to play their music. Ever wonder why flipping around the stations on FM doesn't net you very much difference? Sony doesn't wonder.