i dunno about their rail coverage, you'd probably just have to bring them into a shop, because all people are going to do on here is speculate (plus i think you're the first person to have something go wrong with their 4frnts, so most of us don't know how their warranty works).
as long as the damage isn't directly from sliding rails you should be fine, and even if it is, you still might be okay because 4frnt can't exactly show a ton of pics of guys sliding rails on their website and then say that their skis aren't meant for sliding rails
-Strode
Abba Zabba, you my only friend