"Every platform object is associated with a global environment, just as the initial objects are. It is the responsibility of specifications using Web IDL to state which global environment (or, by proxy, which global object) each platform object is associated with."
This seems pretty important (maybe this should be a warning?). Can you please provide an example of some prose to use in another spec?
You're right, that's a sneaky requirement in there that probably nobody adheres to. :) I wanted to avoid having spec writers define this, but I am not sure how to avoid it really. We need to define for example that all objects returned from document.createElement are associated with the global environment that the document is associated with, while the objects returned from the contentDocument property on <iframe>s are associated with the global environment in the frame.
Not sure really what the best way for other specs to word this requirement is, yet...