I text in that situation too. And call before I cancel. I mostly drive in the daytime, and it doesn't happen often."I'm here now. White Pathfinder SUV with the blinkers on a few houses down/across the street/on the corner/etc'".
BUT I'm less specific about where I am relative to them. That's because their location is not all that accurate at times. I don't pull into driveways as much as I used to, because 1/3 of the time, the rider walks out of the house next door.