I put a tablet (Nexus 7) in my pocket along with my key fob. The car recognized the fob when I got in the car. I drove somewhere and got out but didn't go very far. I was out of the car for about 5 minutes (ATM stop). The door handles did not retract. When I got back in, the car seemed to not recognize the fob. The message in the center of the instrument screen (not sure that's the right term) was "the car is off" or some such. Placing the car into drive did nothing and same for pressing the park button. The fob was between the tablet and my thigh so I assumed it was being blocked by the N7. But, after I pulled the fob out of my pocket, nothing changed. I clicked on the lock/unlock button on the fob to no avail. I got out of the car, walked away, handles retracted and then went through the normal entry process. The people in the parking lot thought I was a wee bit crazy... I'm guessing that the Tesla engineers didn't anticipate a situation where the fob seems to "materialize" inside the car. I definitely would have been unhappy if it was pouring rain or some such.