This is not a promotion

We got a pleasant surprise yesterday during a visit to our local Kwik-fit. We've had a slow puncture the last few weeks, and took the car in to get this fixed. Much to our surprise, they fixed the puncture, showed us the piece of tubular metal that was deflating our tyre, and then refused to charge us for their work. Presumably this is some sort of loss-leader, but it still came as a very pleasant surprise.