Touch screens and mixed user interfaces on things like cash machines, petrol pumps, etc kind of bother me - maybe later posts will go into this as the blog ends saying there will be a follow-up. Just a couple of anecdotes - the first being cash machines where I input the PIN using the traditional buttons on the numeric pad, then i start using the touchscreen to make other choices. Pick one or the other, not a mixture…
Re: calibration: In Austria we have touchscreens for buying train tickets at the station. As a tall person looking down on the screen I always have to factor in some offset, touching slightly beneath the thing I want to hit. Not that bad with big areas. But typing out stuff on the software keyboard is terrible.