I know the colors of scarves mean something but for me I want to just focus on the scarves. Here's a bunch of scarves in MULHOLLAND DRIVE.
First Scarf on Aunt Ruth (leaving Havenhurst with Bags):

Second Scarf (leaving LAX with bags):

The Cowboy (gosh darn it, it never occurred to me that The Cowboy had a scarf but there it is)

Now the 4th scarf (leaving Sierra Bonita with bags):

And while I got to scouring the entire movie for scarves, I found another. I know I'm new to all this but I still love the feeling I get when I see something I didn't notice before, so maybe this is old news but hey.
Guess who else has a scarf? Worn as a cravat. Yep. The Magician. The guy who tells us it was all a dream.

And now finally, Camilla gets a scarf:

I think it's clear that Camilla, in the final scene, is sharing a special component of mysterious folks inside Diane's dream. So now if you consider the pool party scene to be a real world event in Diane's life, a flashback, then Camilla's scarf is just showing up on characters who have special mysterious powers, and furthermore, they are always packing their bags and leaving. Make of that what you will.
But I think scarves mean that the person wearing the scarf is practiced in the arts of manipulating or setting up a scene in the dream. Aunt Ruth and her doppelgangers leave dream scenes just as Diane, i mean Betty, is arriving.
The Cowboy can change what happens in the dream by teaching Adam he has to release control over his film.
And then the Magician shows up with a scarf to basically pull back the curtain on the dream and tell her it's all a tape, a recording.
So then what does it mean that Camilla is now wearing a scarf. I think it means that the moment Rita went into the blue box, she became like Aunt Ruth, The Cowboy and the Magician. Make of that what you will. That would mean that the dinner party scene is still a dream.
Although can't say for sure it if is a scarf or not, Ed has keys like Aunt Ruth.
Would it make sense for him to have a scarf as well?
