My brand new KitchenAid electric smooth top suggests I shouldn't use aluminum or copper based pots/pans as they my leave permanent marks on the cooktop.I really like the looks of the All-Clad MC2 line, but they are brushed aluminum and this makes me concerned. KitchenAid said the marking may or may not occur...All-Clad...well I can not get a human being on the line. Does anyone out there have any experience using aluminum based cookware on a an electric smooth top?