I'm not disputing that Whistler's policy is that it is ok to duck under ropes. That seems well established, and I wasn't really doubting it when @oldgoat mentioned it.
My issue with it is that at most other places, ducking a rope is a major deal and in many cases an automatic pulled pass. Thus, Whistler having a policy that "you can duck a rope in this, this, and this circumstance" blurs a line- there it is officially fine, other places you can get arrested.
One example- At Wolf Creek there is a ropeline running immediately to the right of Alberta Chair near the top terminal. There is a very small slide path in that area that could possibly impact the lift in a climax slide, but reality is that it is stable 99% of the time.
Terrain on either side of the ropeline is open 99% of the time, but access to the far side of the ropeline is restricted to those who hike 50 feet up to the ridgeline to drop in (at Step Bowl). It is managed this way partly to make skiers ski the fall line through the slide path, partly for gaper management, and partly to preserve fresh snow for those that invested in the hike.
One day last season I witnessed a guy trying to duck under the rope without the hike. Terrain on both sides of the rope was open.
Patrol's response to the guy of maybe 17 was "Hey Asshole! What the F%^& is wrong with you? Get the hell away from the rope! We string ropes on this mountain to keep people alive- What do you think makes you so F&^%ing special that you get to ignore them? If I see you again I am taking your pass, and if I see you anywhere near a rope again I'm having you arrested."
Again, this was ducking a rope where both sides were open, on a day where the area in question was just not going to slide. But that isn't really relevant- in patrol's eyes if the guy was willing to duck one, he would be willing to duck another that could be more consequential. I could see within the realm of possibility that the skier had skied WB or somewhere where the ropeline was not a black and white affair.
Just saying- I think WB could change things where they aren't roping off actually open terrain either through gates or signs or the methods that the other 95% of places use.