Just got the Triumph last week and took off the extra screen protector from the factory, it was thicker then I thought it would be. I had the Optimus V before and never used a case or screen protector, keeping it in my pocket with keys or change with no problems. I can understand why people are cautious though.
Update: Not sure if there is a residue left on the screen or what it is, without the screen protector the glass really grips my fingers and is a lot more sensitive to any moisture.
I've tried skinomi before on my tablet, maybe I'll have to try it out on my Triumph.