I been running the extend-ah, since '07 on my C14, and have them on my C10 also....
not saying anything bad about an additional screen, over the rad, but so far I been good... now with the bike I own, being soooooo old, if I do Hole a radiator, I'll snatch one off e-bay, or fix it myself, and apply the big 5 gallon bucket paint roller screens I bought from home depot, project, to the protection thing.. but I'm lazy..those silly roller screens cost me $5 each, and I have 2 in case I screw up....
MOB, I thought the same about not having a Radiator screen, {ie; So far / so good}.
I saw a Buddy hole his rad by a rock thrown up by another bikes tire.
Luckily I had a trailer and he only had to set by the road for about an hour.
{and} I then hauled his bike home and he rode mine...
Bottom line; The bit of protection offered from any Rad Screen, beats setting on the side of the road in the boonies, and/or having to pay to get the bike hauled or fixed.
Ride safe, Ted