I think he's paranoid about his iPod files being left on that PC. (The other way around from your analysis Code Monkey)
And the answer is no, the files from your iPod will not be copied as temp files.
If you access the files on the iPod they can be listed in recent docs and the registry. Just a normal part of what Windows does. They can be cleared out of those places as well (with Tweak UI), but that is a Windows question, not an iPod question.
Have you backed up your iTunes Library this week? If not, you are risking losing your music and playlists....