MailForms don't work on the public page of private sites (usually system:join).

When the password or apply options aren't perfect for the website owner's needs, it would be better if they could use a MailForm on the page to get people to e-mail them an application (using additional fields where necessary instead of the single field that applying for membership usually gives the user).

Problem: MailForms on private sites currently give this error message: "This Site is private and accessible only to its members."
The wish: That MailForms would work on the public page of a private site (e.g. system:join)