Thank goodness other 2013+ models hear this. It is unsettling to hear the rattles. When I took the bike in for routine servicing early on, I asked them to test ride to listen for the rattles. They showed me it was the floating brake pads.
I just switched to a Shoei RF1200 helmet and now don't typically wear ear plugs unless I'm traveling far or want my windshield fully down. With the much quieter helmet I notice noises much more frequently. I do wish there was a way to quiet the brake pads down, but I don't think messing with brakes that were designed to float would be wise for me.