I had one driver "forget" to end my trip (and I called him several minutes later when he was a couple miles away, still on "my" ride) and another driver almost "forget " to end my trip until I reminded him before I left the car.

Driver one did some sort of manual over-ride of the fare and it ended up being a bit less than it originally should have (probably to avoid a later complaint).

I've never had a driver forget to start, and now I make sure the drivers don't forget to end.