I tried to find an article or something that might have had a witness to the incident, or more detail on what happened. But nothing really came up other than the court case that seemed to claim that the operator saw what was going on and willfully chose not to stop the lift (?) .... which seems like an odd claim. I've also seen a couple articles that mention that there was no operator at the controls, which is certainly an issue in my eyes.
I was a lift operator for a handful of years in the early 2000s...I will say even if you are right next to the controls, there are things you can miss regardless of how attentive you are. Once the person is loaded (and appears to be safely seated), your attention immediately turns to the next group coming down the ramp to load. Things can happen in that split second right after you turn your attention to the next group. A ski gets caught in the snow, you drop a pole, or you appeared to be safely seated but in reality, you were a bit off-kilter. The lift is loud when you're right under the bullwheel, there's very little chance you're hearing someone yelling from a chair that just left the terminal.
I don't want this to come off as victim blaming but more a public service announcement: If you (or your kid) are not properly seated in a chair as it starts to leave the terminal, and you're not 100% sure you can get yourself back onto the chair ... DO NOT hold on. Just let yourself, or your kid fall when the chair is close to the ground. This is probably against every natural instinct...especially when it's your kid. But it's likely going to be a better outcome.