My fear with this approach that it allows to write "using namespace moustique". This would cause: - name conflicts on the listen function. - Code harder to read since it's not obvious anymore that listen comes for the moustique library.

I often use namespaces but I do think that they can have a bad impact on the usability of the api, especially when you have too many deeply nested namespaces, and have to use plenty on using namespace ... to fix this.