Driving on ski hills?

I was driving up Keystone Gulch today and was told to turn around by one of their security/mtn. ops guys. It wasn't a huge deal since the trail is pretty boring (except for the views) and I found a better trail anyhow. Still, this is forest service land and I'm upset on principle. This is listed on the FS website as a legal off-highway trail and I've driven through many ski areas before with no trouble. Anyone else get flak from a ski area employee? I do understand that there are certain caveats, i.e. ongoing mtn. operations, emergencies, etc., but this wasn't explained to me - I was simply told to leave.

 

if it's an established FS road then i don't see why you couldn't be on it as long as there are no gates closed. you could ask Dark Knight on here as he works with Keystone, but i don't think they have any authority to tell you to leave a forest service road.