If you create a Wiki page through the web interface and you put a forward slash '/' on the title (e.g. 'foo/bar') the server spawn a HTTP 500 error. The file is created on the repository (foo/bar.md).
If you create a page called '#foo' bitbucket does create a '#foo.md' on the repository but redirect you to '/wiki/Home#foo'.
I think that URI reserved characters should be URL encoded.