yeah, but ski patrol will ban you from the hill if they see you, and if you're hiking a groomer, they will see you.
I remember on opening at whis, this guy was hiking, and the people in the gondola yelled at him like the ski patrol. He actually fell over, and dropped his board. He was scared shitless, cuz he knew what a waste of time it would be if he was caught.
Some people make a trail in the summer in the trees, but other than doing that, likely wouldn't be worth it.