I think this video has been posted a couple times here and there, but I haven't seen a thread dedicated to it. In the early 90's Winter Park took out the Eskimo Chairlift in dramatic fashion.
There are a few tests done, but the the interesting ones can be found at
4:28 - Rollback test
9:52 - Tree falling on haul rope test
11:27 - Fire Test
So I think it's safe to say if you're on a lift that's rolling back faster than the speed of a detachable lift, it would be in your best interest to jump off before you reach the bottom.
This test is old though. I think some resort needs to test a high-speed quad in this manner
So I've seen portions of that film...but not the whole thing. Interesting to say the least.