I have two nice Viewsonic 22" LCD monitors on my desk. I like them a lot.
But clients/family persist in poking their greasy fingers into the screens.
I might be showing them a web page and to draw my attention to something they push into the plastic layer that covers the LCD.
LCD's are not like CRT monitors. Sure, some have a glass front but its rare.
They are harder to clean and more delicate than a CRT.
A big fat fingerprint in your centre of view can be quite annoying when you have to look at it for 12 hrs a day.
So keep your fingers to yourselves.