I did hear a story, but I don't know how true it is.
A guy used to park his 2.0 Capri Ghia at Luton Rail Station every day at around 07-00 hours and return at 18-30 hours.
He noticed that sometimes there seemed to be less fuel in it from when he parked it and a couple of times he sensed it was not in the same parking bay. So he checked the mileage and a couple of times a week it would have gained about 35 miles.
He spoke to the Old Bill who were singularly unhelpful. So he got a square piece of wood about 6" square and a very long nail which he drove through the centre of the wood and then sharpened the end of the nail. If you are squeamish, read no further. When next he parked it he put the piece of wood with the nail upwards right under the driver's seat in the centre of the seat base. The top of the nail was just touching the underside of the seat top fabric.
A couple of days later he came back to find the car unlocked and a big mess of dried blood on the seat. An instant operation for piles?
It makes your eyes water just to think of it, but what a result!