For analyzing the result, I step framewise through the resulting animation.
During frames 6-32 I see the scarf passing through the dress, and around frame 50 the scarf passes through the head, to land on the ground later on.
To repair for that
- I open the sim settings in panel 1, and check the Cloth self-collision option (lowest from the three offered). Although dress and scarf are separate objects, they are both clothified in the same sim. That is meant by “self”. Not only dress-to-dress and scarf-to-scarf but dress-to-scarf as well.
Every time there are multiply objects clothified in the same sim, this option should be checked to prevent on passing through another.
- I open the collision settings in panel 2, for Alyson. I had checked the Ignore head collisions since I guessed that I could afford that, but I was wrong. So I uncheck this one.
Note that when the scarf lands on the ground someway, I’d better uncheck Ignore feet as well to prevent the scarf from falling though them.
In panel 4, I [Clear Simulation] and [Calculate Simulation] again. In the result I see the dress coming at rest soon after frame 60, the free swaying scarf dangles a bit even at frame 90.
This is my result at frame 75.