Not to mention labels lifting and jamming the drive, peeling off the coating (very possible if you leave any bubbles of air which expand when it gets warm and rips a little circle of coating off the CD) and other possible physical damage.
I never use a label on anything important (and I'm far too poor to afford or to run a Lightscribe printer at the moment).
I use them only for the "discs in use" which I can easily do again should they go awry.
I haven't had an unplayable one yet but there's still time ;D
I do have paper labels on my "copied to CD" vinyl collection (several hundred) but, again, I have the originals both on a hard drive and (just in case) on DVDs as well (no labels, just a ref number or similar on the front (and over an unused portion of the disc, if you follow) and, of course, the original vinyls.
As we say in the UK, a "belt and braces" attitude.