They had set out to descend after sunset, and I don't remember seeing any lights on the path. Even a paved road can be dangerous in pitch black.
This. I've had to descend a mountain as the sun was going down once (got stuck at the top due to weather for some time, and when it let up enough for a safe descent, it was late). It's absolutely not fun, even when there's still some light. Had it been dark, I think I would've taken my chances staying at the top rather than going down.
That said, anyone not a complete idiot checks things like "time of last cable car" a) in person, b) at the day, c) at the location. Because even there is an official website that is well-maintained (and that's already two big if's) things might change at the location due to weather, workers being ill, no tourists that day or whatever.
Also, checking in person means at least one other person knows that you're up there.