Why does placing a hand on the Cintiq 27QHD touch display sometimes cause lines to be drawn, how is this avoided?

To avoid accidental touch, first check to ensure the mouse handedness is set correctly under options in the Wacom Tablet Preferences. Second, hold the pen so that when you place your hand on the tablet, the pen tip and your hand arrive on the screen at nearly the same time. Otherwise the software interprets the palm as a touch and makes a mark on the canvas.