Namespaces + RESTful. Why not?

I’m hearing varying opinions on this issue.

Why shouldn’t we use namespaces when using RESTful routes?

Take these two controllers:

Films::Characters
Novels::Characters

They are each managing two different types of model. NovelCharacter and
FilmCharacter.

Though the namespaces, Films:: and Novels:: also have other controllers
beneath that would clash with the controllers of each if there weren’t
namespaces.

I’m not talking about a pointless Admin:: namespace - these are
namespaces that are genuinely needed.

I’ve seen this thread on how to implement it:
http://www.ruby-forum.com/topic/81272

Though is there an easier method?