This dependency should not be necessary for something like printing as it is basic functionality in most browsers (not sure about mobile devices though).
I think your concern about mobile devices emphasizes why this is probably a bad idea: the fact that such a feature would make no sense for many sorts of user agents suggests that it's very fundamentally beyond the scope of HTML. I think that printing is a clear example of invoking page/system behavior, which to me seems like a job for client-side scripting.
Hopefully I'm not off-base here. -- Anthony Jawad
