An interesting proposal from Liam Quin, relating to the need for huge rafts of namespace declarations on mixed namespace documents.
In practice, though, almost all elements [in the given example] are going to be unambiguous if you take their ancestors into account, and attributes too.
Amen. I’ve been saying things like this for five years now. Look at any introductory text on XML, and the example used to show the need for namespaces will be embarrassingly contrived. That’s not a dig against authors, it’s a dig against over-engineered solutions to non-problems.
-m