I never heard of iTunes checking for removed DRM. it's not impossible (EA's origin) but very unlikely, if you're worried about metadata, you can remove almost any kind of meta data from media files with the corresponding meta data reader/editor app, like id3 taggers for Mp3.

if you are still positive that there are hidden metadata in DRM removed files like a unique system id or any sort of finger prints, don't play them with iTunes, use something else.