I think along the lines of malpai about static electricity ,
also 51514brad said the more you lift the cable off the floor the less capacitance was measured , I remember Maple Shade recommending cables be at least 8" of the floor .
I don't think or can't hear a difference but since I got my Cardas blocks for less than 1/2 price delivered so I gave them a try ., tweeks don't always show their advantage all the time , maybe only on certain notes or sounds or maybe under only certain weather conditions .