I had an interesting experience this weekend. I parked my S adjacent to the radio towers on Twin Peaks in San Francisco. Had a lovely stroll, took some picture. Came back to car... Handles don't present. Grab fob, push roof, still nothing. Oops. Could not get car to open conventionally. Tried app to unlock but phone was having difficulty connecting too. Walked away a bit and finally connected (thank goodness the car did) and unlocked to go home. I have since looked up the strong spots for the fob (passenger wiper and base of rear window) But it sure would be nice to have a more reliable backup.