It's not allowed because it's State land and Old-Growth Forest. We can't really change that rule, and its also why the pipe was shut down and why there's a very slim chance of new trails being made (Vickory bowl was a huge, long fight with environmental people).
Though, to be honest, a lot of employees ski in the woods and down the back side. The woods between Upper Balance Rock and Roper's is thinned out and a ton of fun for what it is. Instructors usually won't say anything to you, and ski patrol have more important things to do than chase you through the woods. Watch out for the Rangers though (volunteers in neon orange), they tend to be strict about that kind of stuff. If you do choose to ski the woods, just make sure it's not blatantly right in front of us so we don't get in trouble.
Also: I'm not saying it's okay or that you won't get in trouble, just for the record. So don't come back all pissed if you get caught and someone temporarily pulled your pass.