[Alan]

I haven't used a ladder/step-up as such, I have climbed trees to get a different angle though. Many landscape photographers do carry stepladders in the boot of the car when out. I does work well especially with a wide angle lens, and when you want to get above foliage and similar. It also reduce the angle to the ground so you get a little bit better depth of field as the camera is pointing down more. It's a similar technique that large format photographers use when they tilt the front and back plates to increase dof/focus or rather alter the planes.