Oh. That reminds me of once when I drove my father in his Audi to the pharmacy. When we got there, I let him out at the door so I could go park the car.
But we had forgotten that he had the fob in his pocket. Ooops.
So right after he went inside and I started to drive away, a little yellow key warning popped up on the dash, telling me that the fob had left the car!
This was a totally new situation for me. My only thought at the time, was to make sure to NOT accidentally turn off the engine, since I (assume I) had no way to restart it without the fob.