I just did an experiment:
I took a cotton swab and held one end lightly between two fingers.
I placed the other end on the touch screen applying no pressure.
The touch screen reacts. So it's not pressure sensitive.
Also for seeing the IR with a camera: I'd think the IR transmitters are not on all the tiem but only emit a very short pulse every so often to conserve energy. This pulse will not be seen by a camera.
also refer to
http://en.wikipedia.org/wiki/Touchscreen#Infrared
and
http://www.touchscreensolutions.com....echnology.html
Regards
Aydan