Not all bikes. It's definately more common on carbon frames and lighter alloy frames but you do find the odd one on others as well. You can usually tell by running your fingernail over the edge of them. The LBD are about 50% thicker than the other decals on the frame (although sometimes they clear-coat over them so this isn't a fool-proof approach).

As for forks, I didn't know they were using them on forks. Is this a relatively new thing?