I think George is refering to Hi-temp silicone caulk/gasket material, not silicone grease.
Here is an interesting OPINION about caliper pad "glue/paste" from this site (brake squeal section):http://www.salemboysauto.com/salem-faqs/default.asp?Action=Q&ID=67
"Can I polity disagree, #1 about your use of pad glue and #2, you non use of moly grease?
Extensive testing has proven that what you want is a movement of the pad...to release the dynamic stress that builds in the friction material. When deceleration occurs and stick_slip generates that deadly harmonic energy, it must be dissipated and unfortunately there are only two paths for it to go."
"Well you may be asking, what does this do for me? I hope it gives you pause to look into the new technologies that are available to the automotive industry, especially with respects to servicing and maintaining brake systems. One area I am especially interest in having you consider, is your use of the "glue" type product on the back of the brake pads. I know you alluded to your preference to glue over grease but I wanted to mention that all European and now most every American brake manufacture (Raybestos, Wagner, Bendix, Autospecialty, Qualitee, Performance Friction, etc, etc, etc) frown on a glue type product for pad backs. What they do specify is moly based synthetic lubricant that allow the pad to move freely, wear evenly and also dissipate heat and energy properly. (See our original OE Approved Pastelub 2400ºF Synthetic "Dry-Film" Brake Lubricant on our website, www.gwrauto.com.
Just a sales person opinion, mind you. But, my investigation SEEMS to indicate that more people are now using a "lubricant" on the pad packs instead of a glue. I think Honda manual's specify Molykote 77 lube.