It appears that the Chromeless SWF examples in the ExamplePlayer don't remove their traits when used in a CompositionElement. I presume it's because ChromelessPlayerElement doesn't override setupTraitResolvers(). I tried fixing this by adding trait resolvers similar to DefaultTraitResolver, but had no luck. The SWFAudioTrait, SWFPlayTrait, and SWFTimeTrait never get removed so the media element always thinks the element has these traits even after the composite element has moved on to the next child.
What I'm trying to do is remove a ChromelessPlayerElement child from the parallel element and subsequently remove the traits associated with that child. When I add a VideoElement in it's place the VideoElement has the SWFPlayTrait from the ChromelessPlayerElement instead of PlayTrait.
Can you post some sample code to show the problem? I tried putting the ChromelessPlayerElement in a SerialElement, but when playback of the chromeless child completes, the SerialElement does reflect the traits of the next child. So I think we'll need some code to see the problem, as well as what you're trying to do (it's not clear to me why you would want to remove the traits after you've removed the element itself).