You have to be strict about it - if someone gets hurt skiing a closed trail, they can still sue the ski area - odds are the lawsuit will be thrown out, but nonetheless it still costs money to get the case dismissed.
Another issue - though not one at Killington - is snowmaking. Fan guns require power. As a result, if a carriage gun is on the trail, there likely is a power cord hooked up...sometimes these can be hidden under a layer of pixie dust. Ski edge cutting into a power cord hooked up to high voltage power = Kentucky Fried Skier.
I know there are always going to be circumstances that may change the situation. I'm just saying that IF they pull passes on every poach, i think thats harsh. All i say is that it, unofficially, should be on a case by case basis. Which is what it may very well end up being. Obviously, they arent gonna go on the internet and say, hey guys ski closed trails, we dont care.