CD Protector Snap-Ons?

[Neipas02]

This may be off topic.. But I'm wondering if these can be used to protect dvd games while you're playing them.

If you're not sure what i'm talking about i'll try my best to explain. There was a television commercial not too long ago advertising these little plastic disc covers that popped onto the underside of a cd. They actually had a little lip that slipped over the top so they would stay in place nicely. They showed it on while the cd was in use.

So.. I guess the weight distribution wouldn't be an issue and i'm sure these things weighed next to nothing to begin with.. Just wondering if anyone has ever tried it. I'm going to go search a bit and see if I can even find if they're still being sold anymore..

Any feedback would be nice.
This would be good for games like GT4 and God of War that aren't easily backed up (if at all).