Well, in the typical cd player, there is 3 db headroom above 0dbfs in the analog stage. The systems, over time have reduced the gain out of the dac (most likely due to reduction of stages to even a cheap single chip solution) and due to this gain structure change in cheaper units, the signal needs to appear hotter. so we hard limit, that causes the dac to translate the signal to a higher voltage level than what 0dbfs can do. This really trashes the audio for you guys that really listen to music btw.
I personally hate it, and even other professionals (like Bob Catz) hates this, but we do it because the guy who writes the check says so. Whats even worse, is the newer musicians think that a mix form my mixer should sound like that (which should never happen, thank you). My mixes resemble more like a wave like you see on a mid 70's record. Then I send it to someone like Bob Catz, who slams it through his $10,000 limiter and some light eq.