Had a rather interesting experience about 300km from home yesterday.
The Jaguar has a start button which functions when the key is in or very near the car. Once started I believe it will keep going even when the key is out of range.
We were coming back from a week on Elba and we stopped to eat some lunch in a rest area and then fill up with fuel when I discovered the key was missing from my pocket. There was a moment of panic because I had visions of putting the key on the roof of the car when rushing to get a few things packed away before disembarking from the ferry. I searched my bag, down beside the seat in case it had slipped out of my pocket and everywhere else I could think of. In the end, with a certain amount of trepidation I pushed the start button and the car started. I concluded that the key was somewhere in the car but without unpacking the car entirely I was not going to find it.
We had a couple more stops on the way home, fortunately without problems. In the end I found the key when the car was almost entirely unpacked. I then remembered that I had probably put it in my hat, which I put on top of various bags, to leave my hands free to shove a few things into various spaces (we always take enough for a month when we go away for a week

) the hat then got turned the right way up completely forgetting about the key which proceeded to slip between the bags and things seeking a secure hideaway

Just as well I didn't leave it on the roof of the car. That would have been a nice disaster.