I don't think you'd be immune to the risk by practicing cautious dwnloading. This is why, after learning about this risk, I don't download files off of limewire anymore. Mainly I just go on to browse what other people have. Honestly, if you take a screenshot of the file names that pop up when you type in some words, it shows the obvious implied content.

I don't really see why law enforcement goes after purposeful downloads either, it's data, go after the people making the stuff.

Best way of making sure no data is recovered.
1. take hard drive out of computer
2. Lay it on a flat hard surface
3. Take hammer and smash it into dust.
4. then dump into salt water.
5. dump it's pieces in different places.
That and only that will make sure it is never found on your computer.
Data recovery is so far ahead of the game that no program will delete it. Don't think for a moment it is. I don't care what you want to delete old pictures or tax returns Never give a hard drive away with the computer, never think that hard drive is dead and put in the trash, make sure take apart a burn the disk in. Now for flash memory it is in old cell phone or camera same hold true. It can be recovered.