When people say the Half Dome cables are "down", it does
NOT mean the cables are gone!!!
All it means is that the 1" galvanized pipe "legs" (stanchions) that are stuck into holes drilled into the granite, and supporting the cables at waist-height off the rock, are gone. And of course the wooden 2x4's are gone, too. The cables are NEVER taken away. They are just lowered down to the rock surface. This way, winter snow will not slide down and ruin the pipes.
Many people climb Half Dome in this situation and everyone still uses the cables. All you do is pick up the cable and use it to pull yourself up. In effect, the weight of the cable gives you much more traction on the granite, so you do not slip nearly as easily.
The part that is more difficult is that the weight of the cables can give you some strain on the back (it is maybe 20 - 25 pounds). Also, there are fewer resting places since the 2x4's are gone. But there
are cracks and places along the granite where you can get a foothold and stop to rest.
Hope this clears things up. (Does anyone have a picture of the cables in the "down" state?)
Edit: I finally found a picture with the cables down. Click on the picture for a larger view:
<img src="http://stevec.smugmug.com/photos/115049144-Th.jpg" border="0" Or
click here for the full-size original.