I realize that there have been multiple discussions about positioning the CA FasTrak toll tag (transponder) properly for the Model S, but here I raise a slightly different issue. Many earlier owners experienced problems finding a location to place the toll tag, probably due to metallic coatings on their windshields. I find that in my 2017 Model S, there is no such problem, and I am able to place the toll tag anywhere on the windshield. The Bay Area FasTrak* Customer Handbook seems rather loose about placement, and I am inclined to place it to the left of the rear view mirror base. I've also thought about making a thin black plastic case to mount there, allowing me to easily slide the toll tag in and out of the case, making the whole thing less gaudy looking from the outside. Is anyone aware of more stringent placement/visibility requirements (for example, must the FasTrak logo on the toll tag be visible from the outside)?