considering the labels are totally unnecessary, i don't see the problem. it's not like people are going to be plugging USB cables into the thunderbolt ports or the power cable into the HDMI port by accident.
Still, there is something of a problem in that sometimes people plug things in while the power is off, and computers are often kept tucked away in dim corners. Looking at the machine from an angle, it's not always obvious which connectors are where, especially if you're not a techy who could name ports in their sleep.
My Dell U2410 has buttons that detect when your finger gets near them (they start lighting up) which is pretty slick. Maybe it's just a bit more expensive / harder to integrate and wasn't considered worth it. Not exactly sure how it works but I think it uses the same physical phenomenon as a theremin. Again it's mostly pointless, but it is pretty slick.
As long as the machine is plugged in, I don’t think we can speak of it as being completely off. I suspect the LED illumination will work even when the machine is turned ‘off’. Even if the computer is not plugged in, the LED illumination might work, provided the machine has a built-in battery. At this point in time, we just don’t know. I’m going by the amount of thought Apple usually puts into its products.
