I finally got around to buying a couple of extra RFID keycards for my Model 3 so I could use my watch as my emergency car key. It took me a couple of hours to do the entire job (about an hour and a half was just waiting for the plastic portion of the card to dissolve. After carefully removing the chip (with antennae) and drying it off I brought it to the car to make sure it was already set up with my car (it was). I then carefully unbent and rebent the thin copper antennae into the shape I needed to fit inside my watchband (I made my own watchband years ago using velcro to get a more exacting fit), retested to be sure it still worked (it did). I then covered the Chip & Antennae with Cellophane tape and inserted it into my watchband. Turned off my bluetooth in my phone and have been testing it over the last 2+ days (it has worked every time). Since my watchband is basically nylon there's no damage to the B pillar when touching. I have also used an old hotel RFID card as a block to the Frunk emergency release (again using velcro to keep it in place) after reading about the Frunk opening @ highway speeds when something in it accidentally hit the button.